I ran into the issue where the Windows 10 upgrade installation would fail because “We couldn’t update the system reserved partition”. Thankfully, there’s an easy fix for the problem.
Simply continue reading or skip to the list at the end for the good parts.
So, the problem is basically that your boot partition has too little free space. Now, there are a bunch of solutions to this, but the easiest is to simply move the boot (or “system reserved”) partition to the main partition. If you, like me, have a separate smaller boot partition (usually around 25-100mb), you can download EasyBCD to copy it over to your main partition, which is usually the size of remaining storage space of the drive, so it should definitely be plenty enough.
The reason you have a small separate partition to begin with is because of backwards compatibility. Some really old machines (or more accurately, old BIOS) can’t handle the humongous partitions of today, and so a smaller one is kept to make sure that the OS can boot up on any old system. Needless to say, you probably don’t need this.
- Download EasyBCD
- In EasyBCD, goto “BCD Backup/Repair”
- Choose “Change boot drive” under “BCD Management Options”
- Press “Perform Action”, make sure C: is selected and confirm.
The upgrade should now pass smoothly. If everything works you can remove the old partition, which now serves no purpose.