Sorry for top-posting this, but I think it's an important issue and people shouldn't mess with their device in ways that aren't required. If you've been getting the 0xc1900200 error after an update, some people have already posted that enlarging the system reserved partition is a solution that works (as long as you have enough free space on the C: drive as well). However, there is a simpler way to achieve just enough free space, while avoiding tools like PartitionMagic. Microsoft provides a good description of the solution here: https://support.microsoft.com/en-gb...m-reserved-partition-error-installing-windows For me (with a GPT type drive, which I would assume everyone with the Z83-4 has), it came down to just emptying the folder EFI\Microsoft\Boot\Fonts on that volume. It frees up about 15 Mb and that's enough for the update to go through. Please follow their instructions, it only takes a minute and requires no special tools. Hope this helps, it took me quite some time to solve this very annoying problem. ----- As an additional tip: if you are having trouble getting enough free space on the C: drive for something like the Windows 10 upgrade, where you only need *temporary* space, you can do the following for some folders, like Windows10Upgrade: - insert a storage device on USB and move the folder you want to temporarily relocate (you'll be asked to provide admin rights in some cases - don't move essential system files like this!) - open a command prompt as admin (open start menu, type 'cmd', rightclick the command prompt icon and select 'Run as administrator') - then go to where the folder you moved was, for example 'cd \' to go to the root of C:\ if you moved Windows10Upgrade. And enter 'mklink /J Windows10Upgrade D:\Windows10Upgrade' (assuming your USB device shows up as 'D:'). Once the upgrade is done and you've cleaned up any remaining temporary files, you can either just remove the link and delete the files, or if you moved files you still need, you can just delete the link and move the folder back to where it was before.