Can I delete MSOCache?

Short answer: no. You would most likely no longer be able to perform a repair or install additional components.
I have tried it myself on a virtual machine running Windows 7 with Office 2007–I imagine it would have the same effect on Office 2010.

A safer option (as suggested here) is to burn the folder itself to DVD or move it to a USB drive, and change all references to it in the Windows registry.

From that page:

Solution, what I did recently:

  1. Burn that whole folder to a CD-R or DVD (the filesize of that folder depends upon your Office version).
  2. Delete that folder.
  3. Search the registry in RegEdit for C:\MSOCache and change all references to point to your CD/DVD drive, example: E:\MSOCache (will of course require the disc when something Office related needs those cache files.)

Way to go would be Junction Point.

For example, if you have 120 GB SSD Drive as C:, and 3TB Drive (Magnetic) HDD as D::

  • on drive D: create sub folder named C
  • cut and paste folder MSOCache to subfolder C located on drive D:
  • run CMD
  • type: CD \
  • type: MKLINK /J MSOCache D:\C\MSOCache
  • type: EXIT

After this you will have entire content of MSOCache folder in path C:\MSOCache, but physically files would be located on D:\C\MSOCache.

That was the answer about MSOCache folder on C drive. Now let us talk about a real problem, the same one I experienced few hours ago.


The main problem here is Windows Installer, and their crappy system of caching all old installation files. Every old version of some software that once existed on your PC Windows Installer keeps in his cache folder. Stupid thing, don't you think (only because someone might Uninstall some application Windows Installer keeps all files so it could roll back to the previous state - in simplified version - believe me it's much more complicated, but accept this as is).

This wouldn't be much of problem if there aren't even bigger stupidness again from Microsoft, of course, called Windows Updates. That simply floods you with updates. And what are the Updates!? Nobody!? Updates == Installations == Bigger and bigger Windows Installation Cache.

My situation was I've installed literally base development PC with minimal Office + VS2005, VS2008, VS2010 - That is I must have. I had this on XP machine primary disk with 120 GB just fine and plenty of drive space left with all updates installed (~100GB). But Windows 7 == 30 GB free space (Imagine my face when I saw that). I know windows 7 is little bigger but not 70GB bigger.

... and now 2 hours later I am back to 70 GB ;) HOW you ask me!?

Simply performed same thing as above for following folders:

  • C:\Windows\Installer\
  • C:\Windows\SoftwareDistribution\

Commands are very similar:

  • move above folders to (for example) D:\C\WINDOWS
  • run CMD elevated as an administrator
  • type: CD C:\WINDOWS
  • type: MKLINK /J Installer D:\C\Windows\Installer
  • type: MKLINK /J SoftwareDistribution D:\C\Windows\SoftwareDistribution
  • type: EXIT

Notice only to stop Windows Update, Trusted Installer, and Windows Installer services before moving those folders, run them after if you wish or simply restart (10 seconds for a reboot on SSD).

I have reclaimed back 40GB of (100% uselessly taken space, since I will never uninstall anything I use). Haven't broken any windows rules, since they use for Documents and Settings same Junction Point to Users although on same drive...

Still poking around what else I could move to (Magnetic) HDD drive... One thing to notice you will have winSxS subfolder in Windows folder DO NOT MOVE this folder as it would defy the purpose of Solid State Disk (fast loading of applications). WinSxS is a folder where all Side by Side dll's are located (and prety much every application uses something from there). This is also Microsoft's solution for DLL version HELL, if you wonder why it exists.

The Local Install Source (Msocache) feature is installed so that you do not have to insert the CD during the following Setup operations:

  • Detect and Repair
  • Demand Install
  • Maintenance Mode Setup
  • Installation of service packs and patches

You can use the Windows Cleanup Wizard to remove the Msocache folder. To do this, follow the steps in the related Microsoft article.

Warning: Never delete the MSOCACHE folder by using Microsoft Windows Explorer.