Tag Archives: windows 2008

Windows update CAB file build up

We’ve had a spate of PCs filling up their disks recently, and it seems to stem from a bug in Windows update.

The issue occurs because an accumulated update log file grows, and generates a series of CAB files “cab_xxx_x” in the temp folder (normally c:\windows\temp).

The issue isn’t new, I found references to it dating back to 2012. It seems to be a bug with Windows Update on Windows 7 and Windows Server 2008 R2.

If you just delete the CAB files they will come back. The solution seems to be to do the run the following commands:

net stop wuauserv 
net stop trustedinstaller

rmdir /s c:\windows\softwaredistribution
del c:\windows\temp\*.* /s /f /q

net start wuauserv
net start trustedinstaller

If you don’t stop the services first you may not be able to delete the files.

Next step is to run Windows update. Windows 7 and 2008 R2 have a huge number of updates to do from a fresh install, which is why this log file builds up. Deleting the files resets the log, but if there are still too many to do the issue may come back.

I set up a monitor on SolarWinds N-Central to check all our clients temp folder sizes and to run the above as a script if it was over 15GB. That should prevent any space issues on-going.

Alternatively just upgrade to Windows 10 and Server 2016 – they don’t have this problem.