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dbminter - 22 November 2021 11:35 PM

One possibility that may have happened is the Full is present, but the Differential is either incomplete due to a deleted file or a file that may have become corrupted.  The Full appears to be complete and not corrupt because it was restorable, but the Differential either had a file deleted from its chain, renamed, or it exists but became corrupted on disc somehow.

That sounds very possible because of the time frame between the original and the Differential, it seems like the Differential really was the first Differential made after the Full Backup (that was able to be restored).  If I had to bet, I would bet that you are correct about the Differential being damaged.

I think it was someone else in this thread who postulated that a file in the Differential chain after the Full was made was probably deleted in File Explorer.  That is probably a more likely explanation of what happened.  Which, unless you're absolutely sure of the file naming schemes being employed, it is best to delete the image files from within Reflect itself versus File Explorer.  Reflect would be smart enough to realize what needs to be deleted and delete only those parts.

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M MacKenrick - 22 November 2021 6:36 PM

First I would like to ask if it is possible to mount or open just a Differential so that files can be copied from it?  If that is possible, he can get the half dozen reports he wrote since the Full Image and start with a new Backup Set, doing it more correctly this time.  

capair45, thank you for that information.  This is the first time my brother has attempted a restore (I haven't had to do one yet) and is still learning.  I'm learning a great deal trying to help him, thanks to this forum.

Dan, thank you for your information.  It may very well be that he erased the Full Image that matches the Differential but what I find curious is that the Full Image he is using was made on the 8th, the only Differential (FAC4D85E20BECC08-11-11.mrimg) he has was made on the 14th (about a week later, which is normal).  So, it appears as if that Differential could be the first one made after the Full Image of the 8th.  I'm also curious as to why Reflect is trying to find a file named "FAC4D85E20BECC08-00-00.mrimg" which has the naming sequence of a Differential backup and appears to be the first Differential in a series because of the ....-00-00.mrmgh.  If the retention rules for the Differentials were to keep three, wouldn't the first Differential have been deleted some time ago?  I am not at all familiar with how Reflect works so maybe it keeps the first Differential.

@M MacKenrick I have to correct something you said that may be contributing to the confusion.

I'm also curious as to why Reflect is trying to find a file named "FAC4D85E20BECC08-00-00.mrimg" which has the naming sequence of a Differential backup and appears to be the first Differential in a series because of the ....-00-00.mrmg

It does NOT have the naming sequence of a Differential backup.  File names ending in -00-00 ARE ALWAYS FULL BACKUPS that start a backup set.  The set consists of the 00-00 file and all others that have the same Image ID (the FAC4D85E20BECC08 portion).

the only Differential (FAC4D85E20BECC08-11-11.mrimg) he has

is trying to find its PARENT FULL which will be the file with the same Image Id followed by -00-00.  If that file is missing, any and all differential (and incremental) backups made with it as a parent are useless, cannot be restored, and probably should be deleted.   This situation would have been apparent if Reflect had been used to manipulate files instead of File Explorer.  It would have shown exactly which members of the set were about to be deleted, and it also would have deleted the -11-11 differential and any other members of the backup set if you chose to delete the -00-00 member of the set.

If you have a Backup Set (all with the same image-id portion) consisting of a full and say 20 or more differential backups, you may delete any or all of the differentials in any order without affecting the ability to restore any of the remaining differentials, as long as the parent full is retained. The differentials represent different points in time. Pick the time you want to restore, select the appropriate differential to restore, and Reflect will take care of restoring any data not in the differential itself by loading the data from the parent full.  You do not have to select the full. It's inclusion is automatic. None of the other differentials including the ones taken between the selected differential and the parent full will be needed or used for this restore operation.   And if retention rules automatically perform deletion of differentials, the process always starts with the OLDEST remaining differential thereby losing the ability to restore from that point in time, but this won't affect the other differentials that represent later points in time.  

Beware though that the rules for any incremental backups in the set are vastly different than what I described above.

Thank you for pointing that out to me Dan. I made the incorrection assumption about the naming sequence. I made the assumption from looking at a screenshot my brother sent me of the files in Windows Explorer and in Reflect and that's what the pattern looked like to me. The time frame of the two Full backups and the timeframe of the three Differentials, made it appear as though that were the case. Looking at it now, it does appear as though he did lose the original Full backup for the set he was trying to restore and there were no Differentials made for the two Full backups in the same folder.  Thanks for pointing that out for me and the information on the Differential and Incrementals.  I am keeping all the information I have obtained here and will send it to him.  I will especially remind him to try to do all the work on his files in Reflect instead of Explorer.

Trying to help my brother has made me realize that I REALLY need to learn more about the use of Reflect. At least I did make a Rescue disc and it appears my Backup sets are in order.  Thanks again.

This is off-topic but I was going to try to insert a picture of the screenshot my brother sent me of the list of Full and Differential files he had in his folder.  I wasn't sure if it is more secure to insert a link to say Dropbox or is it just as safe to insert a picture straight from my computer?