Macrium Support Forum

Windows 10 Upgrade issues

https://forum.macrium.com/Topic3262.aspx

By Scott - 10 August 2015 4:48 PM

Windows 10 is adding an extra partition to many users' systems as part of the upgrade process. It does this by reclaiming data from the end of C:

Effects

1. Incremental / Differential backup sets will not be able to append to chains from before the upgrade.
Solution:
Reflect will handle this automatically by creating a new full backup. However, this will not include the new Windows 10 partition.
You should modify your XML definition to include this new partition to ensure that you can recover your system successfully.

2. Depending on your Reflect settings you may notice that Retention does not behave as expected
In the Macrium Reflect Defaults there is an option under the Backup settings called Retention Rules. Where it says "Retention Rules Apply To", if you have this set to Similar backup sets in the target folder, then new backups created post-Windows 10 upgrade may not be purged as the new backups look to be dissimilar i.e. from a different source.
Solution:
Where it says "Retention Rules Apply To" you can change the option to All backup sets in the target folder. This option determines how Reflect handles retention conflicts when you have backups from different sources going to the same target folder (which is effectively what has happened here with the resizing of the C: partition). By changing the setting you can have retention purge image files in that folder regardless of the data the image backups contain.

Use your judgement as to which option is right for you. It may be simpler to delete the old backups manually.

http://forum.macrium.com/uploads/images/cf4e28ff-ab1b-43ed-b8bf-cbcb.png

By Arvy - 10 August 2015 6:52 PM

Thanks for that "heads up", Scott.

I haven't seen that happen myself, neither with the MS "free upgrade" process (Win8.1 -> Win10) nor with a fresh Windows 10 installation thereafter.  Perhaps that's because all of my OS drives are set up for old-style MBR booting and, in the case of fresh installs, my habit is to create an empty active partition prior to running the OS setup process.

Have you noticed whether that Win10 "extra partition" quirk occurs with UEFI/GPT boot setups in particular, or is it being experienced as a more general phenomenon?


By Froggie - 10 August 2015 7:16 PM

Arvy, based on when that happened with the W8.1 upgrade... folks who are BOOTing through a MicroSloth System Reserved Partition will most likely be the ones affected by this "phenomena."  LEGACY-MBR users with no MSRP (like us) don't see that phenomena...
By Arvy - 10 August 2015 7:35 PM

I strongly suspect that you're right.  Most of the things Microsloth inspires in the name of "progress" seem to me more like encroachments on the whole original concept of "personal computing".  I've never felt any compulsive inclination to exceed the 2TB limit on MBR drives for installing the OS itself.  And, as for that wonderful new "secure boot" feature (a.k.a. DRM restrictions) in some MS-mandated UEFI implementations, the less said the better so far as I'm concerned.
By lagunasrfr - 11 August 2015 9:35 PM

Arvy helped me by leading me to this post. After upgrading to Win10 I did have to create a new full backup. I also think it might hav been involved with deleting my v5 backup definitions and re-creating with Macrium v6 at the same time.
However I now have 7 partitions on my mrimg file whereas befor update I had 5. Looks like two were added.
By babjab - 2 January 2016 10:21 PM

With the recently released  Windows 10 Professional Preview version 1511 (OS Build 11082.1000) Reflect v6 scheduled jobs fail to execute. I found that I had to edit the entries in the Windows' Scheduler and change the "Configure for:" to "Windows 10." Unfortunately when this is done the "Schedule For" entries in Reflect are lost.

Reflect v6 Scheduled jobs running under Windows 10 Home 1511 (OS Build 10586.36) are unaffected.

Since Build 11082 is beta I expect that Macrium will address any problems.
By Arvy - 3 January 2016 2:54 AM

The Windows "Insider Preview" (build 11082) scheduler issue is discussed in more detail in this forum thread.  As stated by Nick in his reply there: "There appears to be a problem with the Windows Task Scheduler in this build that I'm sure will be resolved by Microsoft before public release."  Personally, given Microsoft's Win10 track record to date, I'm less sure of that than he is, but we'll just have to wait and see.
By GTK48 - 7 January 2016 5:51 PM

I just deleted it. I don't need it.
By GTK48 - 19 February 2016 12:48 PM

I removed it since I use MR!
By Arvy - 3 June 2016 2:07 PM

=hankfoner -- My question is: If I ever have to do an Image Backup Restore will it matter that partiton no. 3 is not reinstalled?  [Question was subsequently removed and reposted by its author.]

As Scott has noted in this topic's OP, the Windows 10 upgrade process may add a partition by reclaiming space after the OS ("C:") partition on your hard drive.  The additional partition is most likely a WinRE recovery partition (usually identified by a $WINRE partition marker) and, if so, it may be used by Windows 10 for some reset and advanced start-up repair options as shown in the screenshot below.  WinRE is also included in the boot configuration data (BCD) store for Windows 10 to use in rebooting automatically if it detects a post-bootmgr start-up problem, but it is not usually visible as a boot option during normal system start-ups.

Reflect's option to "Create an image of  the partition(s) required to backup and restore Windows" excludes any such $WINRE partitions, presumably on the basis that they are not actually required for normal Windows OS start-ups.  Personally, I disagree with Macrium quite strongly about their whole exclusionary implementation of that option and Microsoft seems to think that WinRE is important, but you'll have to decide for yourself whether it matters or not.  If you want to add the $WINRE partition to your backup images, you'll have to use the other Reflect option to "Image selected disks on this computer" and include it in your own selection.

http://forum.macrium.com/uploads/images/11ffeb69-849a-4a7e-8ffb-34be.png

By Dypsis - 7 August 2016 8:08 AM

GTK48 - 7 January 2016 5:51 PM
I just deleted it. I don't need it.

Deleted what?
By Arvy - 7 August 2016 11:02 AM

This topic was about "Windows 10 is adding an extra partition to many users' systems as part of the upgrade process" and the post by GTK48 immediately after the one that you quoted said "I removed it since I use MR!".  So, in the absence of any other explanation, I suspect it was most likely the extra added recovery partition that got deleted.  People tend to assume that no Windows recovery partition functions will be needed when they have backup software.
By BGregory - 7 August 2016 3:06 PM

I'm using MBR/Legacy boot with 2 partitions:  Partition 1 is my OS (C), partition 2 is my Data(D).  After the update I had 3 partitions: Partition 1 was my OS(C), partition 2 was a small recovery partition with space taken from C, and the 3rd partition was my Data.  My backup XML file was set to include partitions 1 and 2.  I realized this only AFTER I ran a backup on the updated Win 10 and tried to restore it to a test HD.  My DATA partition was not on the backup (because it was now the 3rd partition).  Fortunately I caught this.  I deleted the recovery partition and added the space back to C, then ran another backup. Just wanted to mention this for anyone else with a configuration as mine..  Would have been nice if Microsoft mentioned this during the update.!! 

Arvy... I deleted the recovery partition because I never needed it in the past. Why would I need it?

By Arvy - 7 August 2016 6:38 PM

You probably wouldn't.  At least I hope not.  On the other hand, things like the Windows OS "Refresh" option rely on its being there.  Maybe even access to "Safe Mode" in some cases.
By peter09aug2016 - 22 August 2016 9:45 AM

After such upgrades like 1511 there are two WinRE partitions, namely the previous one, sized about 500MB, and the new one, sized about 800MB. The previous one is kept to allow undoing the upgrade, and remains registered in BCD. The new one is placed at the end of C: in order to allow for further expansion. All need to be included when backing up The Partitions Needed to (back up and) Restore Windows.
MSR or Reserved (unique to GPT) does not play any role here, and is not to be confused with System, ESP or System Reserved.
I found that in some upgrades, on MBR style computers, there is no new WinRE, whereas in others, GPT style, there was a new WinRE. Sometimes this already happened on the upgrade from Windows 8 to Windows 8.1 or Windows 8.1 Upgrade. There are really various scenarios about where "System" and "Recovery" are placed. They may be separate partitions, or "Recovery" function is contained in C:, rarely in "System", or both functions are contained in C:.

+ Recently I worked on a new computer, its SSD was split into C: and D: . It would have created the new WinRE in the middle of the SSD, when applying the 1511 upgrade. Therefore I combined C: and D: into one C: before doing the upgrade. The SSD needed no splitting as there was another large HDD.
By Arvy - 22 August 2016 3:43 PM

All need to be included when backing up The Partitions Needed to (back up and) Restore Windows.

If you're referring to the Reflect option to "Create an image of the partition(s) required to backup and restore Windows", that has always excluded any and all WinRE partitions in my experience.  Personally, I just select the entire OS drive (all partitions) for my own system backup images.

__
Please Note: There is a more recent Featured Post on the subject of Windows 10 Anniversary Update Issues.
By dyhs - 26 June 2017 12:11 PM

Arvy - 22 August 2016 3:43 PM
All need to be included when backing up The Partitions Needed to (back up and) Restore Windows.

If you're referring to the Reflect option to "Create an image of the partition(s) required to backup and restore Windows", that has always excluded any and all WinRE partitions in my experience.  Personally, I just select the entire OS drive (all partitions) for my own system backup images.

__
Please Note: There is a more recent Featured Post on the subject of Windows 10 Anniversary Update Issues.

Maybe something has changed? I use Macrium Reflect 6.3.1821 and "Backup" - "Backup Windows" automatically selects W10 Recovery (WinRE) partitions too (both of them, on a GPT SSD).
By stuarttunstall - 28 November 2017 8:18 PM

Hi

 I have just updated my notebook to the latest fall version, 1709 and it is now doing a full backup rather than an incremental, which is confusing..

 In the running back up it states full...


But in Reflect it states incremental is runing...



I cant see an extra partition... this is what I see when I open Reflect how can I check if I have any extra unknown partitions? I presume as this is the first screen I do not have any extra partitions?


I presume now a new full is created the incremental/diffential will continue as normal from tomorrow?

Also

I presume it is to do with the above, how do I get it to recognise my old backups if I need to restore back to the old Windows i.e last nights incremental? Can I still restore to my last back up from the old version of Windows if needed? As you can see it shows zero backup sets.. Sad 

STuart
By jphughan - 28 November 2017 9:00 PM

You don't have an extra partition, but what probably happened is that during the Windows 10 upgrade, your C partition was shrunk to expand the size of the partition immediately to the right of it, i.e. Partition 4.  That's the Windows Recovery partition, not to be confused with the last partition on your disk also labeled Recovery, which is probably from your PC manufacturer rather than Microsoft.  Even changing the existing partition layout without creating/deleting any partitions is enough for Reflect to stop making Incrementals on an existing set.  If you want to verify that you're suffering from shrinkage Tongue, then open Reflect, go to the Restore tab, select an image from before the upgrade, and click "Browse Image".  Check the "Capacity" figure for that Partition 4 and see if it's less than the current 969 MB size.

You see "Incremental" in your second screenshot because the schedule does indeed say to run an Incremental.  But because Reflect can't run an Incremental for the reason stated above, it's instead running a Full.  That's why the log says "Full - Incremental specified but...."  Another scenario where you'd get a Full even if you specified an Incremental would be if you connected a disk that contained no backups.  You wouldn't have to create a Full manually for your scheduled Incremental to work; instead, Reflect just automatically switches to a Full when conditions don't permit an Incremental.

Yes, after that unexpected Full completes, your schedule will run as normal -- at least until the next Windows 10 release if the OS partition needs to be shrunk again to accommodate an even larger Recovery partition.  And since Microsoft has said they plan to release new Windows 10 versions every March and September, this is likely to happen more frequently.

Your old backups are still there and Reflect can still restore them; it just can't append new backups to them.  If you wanted to roll back, the process would be exactly the same, although from experience, I can tell you that if you want to roll back to a backup that was created from a previous release of Windows 10, I would recommend restoring your EFI (System) partition, the MSR partition, the OS partition, and the Windows Recovery partition -- or the first 4 partitions on the disk in your case. Note that if you ever did that, the backups of your system after the restore would start appending to your previous image set, NOT the latest set that reflected the post-upgrade disk layout.  If you didn't have that set anymore, then the first post-restore backup would generate a new Full since again, the disk layout would be different from what's contained in the most recent backups you performed prior to rolling back to a pre-upgrade backup.
By stuarttunstall - 28 November 2017 9:10 PM

jphughan - 28 November 2017 9:00 PM
You don't have an extra partition, but what probably happened is that during the Windows 10 upgrade, your C partition was shrunk to expand the size of the partition immediately to the right of it, i.e. Partition 4.  That's the Windows Recovery partition, not to be confused with the last partition on your disk also labeled Recovery, which is probably from your PC manufacturer rather than Microsoft.  Even changing the existing partition layout without creating/deleting any partitions is enough for Reflect to stop making Incrementals on an existing set.

You see "Incremental" in your second screenshot because the schedule does indeed say to run an Incremental.  But because Reflect can't run an Incremental for the reason stated above, it's instead running a Full.  That's why the log says "Full - Incremental specified but...."  Another scenario where you'd get a Full even if you specified an Incremental would be if you connected a disk that contained no backups.  You wouldn't have to create a Full manually for your scheduled Incremental to work; instead, Reflect just automatically switches to a Full when conditions don't permit an Incremental.

Yes, after that unexpected Full completes, your schedule will run as normal -- at least until the next Windows 10 release if the OS partition needs to be shrunk again to accommodate an even larger Recovery partition.  And since Microsoft has said they plan to release new Windows 10 versions every March and September, this is likely to happen more frequently.

Your old backups are still there and Reflect can still restore them; it just can't append new backups to them.  If you wanted to roll back, the process would be exactly the same, although from experience, I can tell you that if you want to roll back to a backup that was created from a previous release of Windows 10, I would recommend restoring your EFI (System) partition, the MSR partition, the OS partition, and the Windows Recovery partition -- or the first 4 partitions on the disk in your case. Note that if you ever did that, the backups of your system after the restore would start appending to your previous image set, NOT the latest set that reflected the post-upgrade disk layout.  If you didn't have that set anymore, then the first post-restore backup would generate a new Full since again, the disk layout would be different from what's contained in the most recently backups you performed prior to rolling back to a pre-upgrade backup.

Thank you for the great and much simpler explanation of how it works, great for a novice like me Smile

I still think Microsoft should give you the option to install updates rather than force them, it has gone well apart from a couple of minor issues with HP Software, the 3D Guard and Coolsense which even after i updated to there so called fix still seem to not work... Sad see what they have to say..

Only other issue is some missing icons in the app section

Name:  icon.JPGViews: 8Size:  36.0 KB

No idea why they are missing and just blank squares...

At least I know if I do get sick of 1709 and find any major issues I can go back to my last (last night) version of 1703 Smile I would indeed restore the first 4 partitions Smile 

Just checked the definition file and went to amend it, as you say shows the same 5 partitions Smile



One other question, when my back up starts and it notifies me it gives you options to not postpone or select a time... the last twice this has said postpone for 4 hours by default, how is this changed?
By jphughan - 28 November 2017 9:10 PM

One more thing in addition to the above: As mentioned in the first post of this thread, as a result of this partition layout change, your retention policy won't purge the older backups anymore.  You'll either have to do that manually or change your backup set matching policy to "all backup sets in the destination folder" rather than your current (and default) "all matching sets".  The latter option will simplify things in this new world where frequent Windows 10 upgrades are the norm, but if you want to enable that, I would recommend making sure that your destination folder for these backups stores ONLY backups of this particular PC.  Otherwise, if you have backups from multiple PCs stored in that same folder, then as the "all backup sets" wording implies, enabling that option could cause Reflect to delete backups made by a completely different PC, rather than backups made by a different "version" of your PC's disk layout.
By jphughan - 28 November 2017 9:17 PM

Stuart Tunstall - 28 November 2017 9:10 PM

Thank you for the great and much simpler explanation of how it works, great for a novice like me Smile

I still think Microsoft should give you the option to install updates rather than force them, it has gone well apart from a couple of minor issues with HP Software, the 3D Guard and Coolsense which even after i updated to there so called fix still seem to not work... Sad see what they have to say..

Only other issue is some missing icons in the app section

Name:  icon.JPGViews: 8Size:  36.0 KB

No idea why they are missing and just blank squares...

At least I know if I do get sick of 1709 and find any major issues I can go back to my last (last night) version of 1703 Smile I would indeed restore the first 4 partitions Smile 

Looks like the attachment about icons didn't show up, but if that screenshot was of your Start menu, that's not unusual for a new Windows update.  Some Start tiles are just stubs for apps that aren't even installed on your PC yet but will automatically download in the background, or for apps that won't install unless you click them.  In the latter case, Microsoft is using the Start menu as advertising space for third-party apps, which is how they're making Windows 10 "free".  You can remove them of course, but Microsoft has correctly bet that the average user won't always bother.

In terms of refusing new releases, Windows 10 Pro lets you defer upgrades until Microsoft certifies a new release as "ready for business" (read: enough bugs have been fixed), which is typically 6 months after the release to the general public, but even there you can't defer forever.  And that honestly makes some sense; if Microsoft is releasing a new OS build every 6 months, it can't possibly keep developing updates for all of those releases for the 10-year support period it's historically provided for Windows.  With Windows 10, Microsoft commits to providing updates for the current release and the previous 2 releases, i.e. right now it's updating Anniversary, Creators, and Fall Creators -- but in March when the next build is expected, Anniversary will no longer be supported.  Enterprise customers get an additional option to deploy a "Long Term Servicing Branch" that Microsoft DOES commit to supporting for several years, but if you install that, you are BLOCKED from installing new releases, so you can't have it both ways -- and thus far the only releases for which the Long Term Service Branch deployment option was made available are the original release (1507) and Anniversary.
By stuarttunstall - 28 November 2017 9:23 PM

This was the image, it is when I click on taskbar settings and what icons to show,. 

One other question, when my back up starts and it notifies me it gives you options to not postpone or select a time... the last twice this has said postpone for 4 hours by default, how is this changed?

I have just changed the setting you stated, may as well have the purge automatically done Wink I do only use the backup drive on this notebook Wink 
By jphughan - 28 November 2017 9:29 PM

I don't remember seeing that, but I don't remember looking for it either.  I know that for a while those "toast" notifications that would pop up in the lower-right corner showed some long unique identifier where the application name should be, but that went away on its own, so maybe your issue will too.  It's possible that there's just some background maintenance/update work that needs to be done, and possibly a restart or two.

I'm not sure if the default postponement option has changed since the only place I use scheduled backups is on a server where there is almost never a user logged in interactively, so I never see that prompt. But if you selected 4 hours at some point in the past, it might default to showing whichever option you last selected.
By stuarttunstall - 28 November 2017 9:33 PM

I have just clicked to run an incremental again and it did indeed say do not postpone so I will check tomorrow Smile 
As I say i have changed the setting regarding retention rules in the default area as shown in this post, but I have noticed if I edit my backup xml it also has that option in there which still shows the all matching sets" do I need to change that as well? or does it work off the default
By jphughan - 28 November 2017 9:45 PM

Yes, you need to edit the definition file and change the setting there.  The retention settings under Edit Defaults determine the default settings for any new definition files you might create.
By stuarttunstall - 28 November 2017 9:58 PM

Excellent, I have just shut the notebook down so I will get that changed tomorrow Smile 

Thanks for all the help and advice with this, made it much easier to understand..

I did just check the restore tab and last nights back up is there as you say, so ifI find any issues with the 1709 update I can go back to the old version for now Smile

Stuart
By norti - 26 December 2017 10:16 AM

Hello

There is a new issue with Windows 10 Insider Preview build 17063, issues to be precise in this case:

- Windows 10 cannot upgrade from 17046 to 17063 if Macrium Reflect and PE environment boot options are installed. Completely removing MR solves this and after that the upgrade goes through.
- After upgrading to build 17063 and installing Macrium Reflect with all the options (except viBoot in my case), restarting the system it goes into bootloop and Windows cannot start. Removing MR/reinstating last known good state solves this.

Obviously something is changed during the boot process in Windows 10 Insider build 17063 (Microsoft hasn't answered it yet), but ith may be something on Macrium's side too.
Can you please check this?

Thanks

I have the Home Edition of MR, latest version.
Windows Insider Preview topic of the upgrade error
By jphughan - 26 December 2017 3:39 PM

This has been reported a couple of times in various places on the forum. Macrium has already replied that they’re looking into it. I’m guessing it has to do with MIG protection. In fact if you’re so inclined and haven’t already tested, do you see this behavior if you choose to install Reflect without the MIG component?
By norti - 26 December 2017 4:57 PM

jphughan - 26 December 2017 3:39 PM
This has been reported a couple of times in various places on the forum. Macrium has already replied that they’re looking into it. I’m guessing it has to do with MIG protection. In fact if you’re so inclined and haven’t already tested, do you see this behavior if you choose to install Reflect without the MIG component?

Tried it without, the same bootloop.
By jphughan - 26 December 2017 5:22 PM

Interesting! In that case I’ll be very curious to learn underlying cause on this and whether it seems to be a bug in this particular Insider release or the result of a deliberate change by Microsoft.
By Nick - 30 December 2017 8:58 PM

Please see this KB article:

https://knowledgebase.macrium.com/display/KNOW7/Windows+Insider+Preview+17063+BSOD
By Kent Reid - 2 January 2018 11:16 AM

I am not technical but, having removed MR and getting Build 17063 to install, apparently MR persists as a scheduled task and stills runs. The HD activity light was flickering at the set time, so I checked task manager and the MR backup process was active. I then checked the partition where the file is sent, and there is a current date backup present. I have now made the change to the registry and will attempt to reinstall MR.
By jphughan - 2 January 2018 3:32 PM

The Reflect uninstaller provides a list of checkboxes asking whether to remove certain things, such as definition files, preferences, and scheduled tasks.  By default those are not checked for convenience in case the user simply needs to uninstall and reinstall Reflect, in which case preserving everything will make that less painful.  If you left the uninstaller at its default settings, that would explain the scheduled tasks still being there, although I'm not sure how Reflect would have actually run after it had been uninstalled, since the application itself would have been uninstalled.
By Kent Reid - 3 January 2018 12:39 PM

jphughan - 2 January 2018 3:32 PM
The Reflect uninstaller provides a list of checkboxes asking whether to remove certain things, such as definition files, preferences, and scheduled tasks.  By default those are not checked for convenience in case the user simply needs to uninstall and reinstall Reflect, in which case preserving everything will make that less painful.  If you left the uninstaller at its default settings, that would explain the scheduled tasks still being there, although I'm not sure how Reflect would have actually run after it had been uninstalled, since the application itself would have been uninstalled.

My thinking exactly. The HD activity was the give-away. I have reinstalled MR and the new image is approximately the same size as the ones that "ran" with the program supposedly un-installed. ​I can view those in explorer, and everything seems to be there. I'm not complaining - just slightly baffled. In any case, things are back to normal. Thanks for your assistance.
By Kent Reid - 3 January 2018 1:23 PM

jphughan - 2 January 2018 3:32 PM
The Reflect uninstaller provides a list of checkboxes asking whether to remove certain things, such as definition files, preferences, and scheduled tasks.  By default those are not checked for convenience in case the user simply needs to uninstall and reinstall Reflect, in which case preserving everything will make that less painful.  If you left the uninstaller at its default settings, that would explain the scheduled tasks still being there, although I'm not sure how Reflect would have actually run after it had been uninstalled, since the application itself would have been uninstalled.

Further to my confusion - Windows confirms that I installed MR on January 2. I then browsed the image that was made on Jan 1. Program Files contains a folder named Macrium and it contains a file named reflect.exe. Does that indicate that the program might not have been un-installed at all, but somehow modified sufficiently to allow Build 17063 to install? ​The executable must then have functioned as normal. For reference, this is how I removed MR. Settings - Apps - Apps & Features - Macrium - Uninstall. Is that route less complete than using Control Panel?
By jphughan - 3 January 2018 2:22 PM

Reflect is a fairly small application, so especially after taking image compression into account and all of the other changes that can occur on a Windows partition from day to day that would affect disk consumption, image size doesn't seem like a relevant factor. The bigger question is how Reflect ran at all after you'd uninstalled it.  I've never used the Settings > Apps path to uninstall applications.  I would've guessed that it would call the same underlying functionality as Control Panel > Programs and Features, but especially in light of your experience, that may not be the case.
By Mintmag - 5 June 2018 6:05 PM

What is the purpose of the new partition?
By jphughan - 5 June 2018 6:14 PM

Mintmag - 5 June 2018 6:05 PM
What is the purpose of the new partition?

It takes over as the new Windows Recovery partition.  It's only created when the existing Recovery partition's free space is below the requirements of the new Windows version you're upgrading to.  The original Windows Recovery partition then just sits on your disk uselessly taking up space because it's typically located in an area of the disk that doesn't allow its storage to be easily repurposed elsewhere.

If you're asking what the Windows Recovery partition does, it contains some tools to diagnose and repair issues that might prevent you from booting into Windows, such as Command Prompt, Startup Repair, System Restore, System Image Recovery, etc.  Additionally, on systems that have BitLocker enabled, the necessary files to unlock a BitLocker partition are stored on the Recovery partition (UEFI systems will alternatively store those files on the EFI partition if the Recovery partition doesn't exist.)  Of course for Reflect users, especially those who don't use BitLocker, the Recovery partition serves little to no purpose -- but even if you were to delete the Recovery partition, it would get recreated any time you upgraded to a new release of Windows 10.
By Mintmag - 5 June 2018 6:30 PM

Doesn't Windows already have a recovery partition?
By jphughan - 5 June 2018 6:43 PM

Yes, but the size requirements for that partition have increased with newer releases, even within Windows 10 releases. So if you try to upgrade to a new version of Windows that requires more capacity on the Recovery partition than your current Recovery partition has, it has to address that. Since the original Recovery partition by default is the first partition on disk, it isn’t possible to extend that one in place. That’s why the Windows upgrade process instead shrinks your OS partition by some amount and creates a new one in that freed up space. After you have a Recovery partition immediately after your OS partition, any future needs can be met by just incrementally shrinking your OS partition by the additional amount necessary to create more space for the Recovery partition.

Of course it would arguably make more sense for new Windows installations to just create the Recovery partition after the OS partition in the first place so that you don’t end up with a “dead weight” Recovery partition at the beginning of your disk later. That incidentally is exactly what the TechNet deployment guide now recommends, but for some reason Windows Setup as of this writing still places the Recovery partition first on brand new installations. One possible reason is that when your OS partition is the last one on disk, it’s a lot easier to clone to a larger disk and extend that partition to fill the new space. If you have a Recovery partition after your OS partition, you can’t do that after the fact; you’d have to stage the clone differently upfront.