When upgrading to Windows 10 it fails with the error WindowsUpdate_80070070 OR WindowsUpdate_dt000 - not enough disk space. According to the FAQ I need at least 8GB in order to upgrade, which I have on all three of my disks. On C: I have less than 11 though. Basically C: only contains Windows 8.1 and the upgrade files for Windows 10, there is almost no other data on there. Is there a way to upgrade from a different drive?

I have run the disk cleaning utility and I do not want to do a fresh install. I checked the drive with WinDirStat and there is no more data I can move or delete on C:. Any hints?

  • Upgrade also backup your Windows folder, how big is your current Windows folder? – Martheen Cahya Paulo Aug 7 '15 at 2:47
  • Much like "the cake is a lie" in portal 8gb is lie, try 16gb! What have you done? I will start a check list. – cybernard Aug 7 '15 at 2:51
  • How many GB are in this hidden folder? C:\ProgramData – cybernard Aug 7 '15 at 3:14
  • Is your C: drive the whole physical drive or just 1 or several partition? If there is more than 1 partition resize the other one and make c: larger. – cybernard Aug 7 '15 at 3:16
  1. Is your hibernation file off? From Administrative Command prompt

powercfg /h off

  1. Did you move your swap file to another drive?
  2. How big is c:\users\

Empty all of these folders

C:\Users\_Your_username_\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5
“C:\Users\_Your_username_\AppData\Local\Microsoft\Media Player”
“C:\Users\_Your_username_\AppData\Local\Microsoft\Media Player\Image cache”
“C:\Users\_Your_username_\AppData\Local\Microsoft\Windows Live\Contacts”
“C:\Users\_Your_username_\AppData\Local\Microsoft\Windows Live\Contacts\your_email@live.com\15.4\DBStore\Backup\new”
c:\program files\NVIDIA Corporation\Installer2

  1. Turn off Windows update Move C:\windows\SoftwareDistribution to another drive and junction it

    mklink /J "C:\windows\SoftwareDistribution" "d:\junctions\SoftwareDistribution"

Turn windows update back on.

  1. Delete all but your last system restore point.
  2. Re-install,Move,Junction the largest folders in

    "c:\program files"

    "c:\program files (x86)"

More in a minute.

You need to move and/or junction stuff to another drive. Is My Documents/Documents still on the C: drive? Move them!

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