Windows updates fails with error 80070bc9

Solution 1:

Logon with administrator rights.

Type cmd in the bottom left windows button

I fix it with:

fsutil resource setautoreset true c:\

Then in safe mode try to delete these files:

C:\WINDOWS\system32>cd %SystemRoot%\System32\SMI\Store\Machine
C:\WINDOWS\System32\SMI\Store\Machine>attrib -s -h *
C:\WINDOWS\System32\SMI\Store\Machine>del *.blf
C:\WINDOWS\System32\SMI\Store\Machine>del *.regtrans-ms
C:\WINDOWS\system32\SMI\Store\Machine>cd %SystemRoot%\System32\config\TxR
C:\WINDOWS\System32\config\TxR>attrib -s -h *
C:\WINDOWS\System32\config\TxR>del /q *

Reboot and it will all work !

Solution 2:

Try installing the oldest update first, and do it one at a time to see if that works. I had a similar issue where the Troubleshooter in Control Panel didn't work, installing the System Update Readiness Tool for Windows 7 for x64-based Systems (KB947821) didn't work, and finally just installing each one, one at a time, while a pain in the ass actually got the 4 updates that were failing to install for me after reboot and reverting back to original state to actually install.