There is a strong possibility that my daughter's Windows 10 laptop from PC Specialist may be going to be replaced under an insurance claim as she accidentally spilled some Coca Cola over the keyboard. I've used Macrium Reflect for a few years now and it has got me out of many difficult problems by restoring a previously-saved image back onto my PC, so I'm quite comfortable with that process. However, I've never used it to transfer everything to a new computer, so I was wondering if anyone could give me some tips to ensure the process runs smoothly? I already have a Macrium Reflect Rescue Disc and I've also created an alternative on a USB flash drive, which might be easier to use, rather than having to use my portable Blu-ray/DVD/CD player.

My plan is to take one last full backup image from the current laptop before it is taken away later this morning. My next step on any new machine will be to make a full backup image to keep ready in case copying the old disc image results in problems. After that, I should be ready to attempt the transfer. Does that sound like a good plan? Also, should I de-register the licence on the old machine and/or uninstall the program before it goes away or is that unnecessary?

JPHUGHAN will probably write you a book on this question since he knows more about it than any other user I'd say.
​
For the license: https://knowledgebase.macrium.com/display/KNOW72/Removing+your+License+key+when+Upgrading+your+PC​
​
You have the basic idea but since you are moving to different hardware, you will need to run REDEPLOY which is on the rescue media. This gets the basic mass storage devices installed so disk operations can work.
​
https://knowledgebase.macrium.com/display/KNOW72/Re-deploying+Windows+to+new+hardware+using+Macrium+ReDeploy
​​​
You could install Reflect on the new machine and make a Rescue disk with it which will include the drivers for that hardware when running the Rescue disk.
If the old machine's disk is setup as MBR you will end bypass the UEFI BIOS on the new machine and I wouldn't recommend this.
Personally, I'd seriously consider just using the W10 on the new machine assuming it is as good or better version (Pro vs Home) of Windows and is a 64 bit version instead of 32 to support over 4GB of RAM. It will have all the proper drivers for the new machine's hardware.

​​ Also, it is a good time to reload only the apps and data files you really need. Of course, this will take some more time usually.​​​​​

Seek is correct that if you choose to restore your old PC's image onto the new one, then you'll also need to run ReDeploy.  And if your old system used Legacy BIOS booting and the new one uses UEFI, ideally you'd want to perform a custom restore process that will allow the old system's image to be bootable in UEFI mode on the new system.  Macrium has a KB article about that.

But call-out about matching the edition of Windows is a good one.  If the "outgoing" PC is licensed for Win10 Pro, and the new PC is licensed for Win10 Home, then when you restore the Pro image, chances are it won't activate -- unless you've got your Windows license linked to your Microsoft account, in which case you would be able to reassign the license tot hat PC.

As for Reflect, if you'll be migrating the system image, I believe you do NOT need to deregister Reflect.  That's only if you'll need to perform an actual new installation somewhere else -- or even on a clean reinstall of the same physical PC, as I learned when I failed to deregister Reflect prior to this and heard from Macrium later on. (I explained the situation and it was fine.)

Capturing an image backup of the new PC before you do anything to it is a very good idea.  And in fact when you've done that, if you post screenshots of the partition layout of the old PC's last backup and the new PC's initial backup, that would help identify whether there are any special steps you should take if you want to perform this restore.