The MSOCache folder contains the Office Setup files, so that to repair/reinstall an Office component, you don't have to insert the Office CD-ROM everytime. If the MSOCache folder is deleted, you'll need to use the Office CD-ROM to repair or reinstall Office components.
Do not use explorer to delete this folder. Just running the Disk Cleanup Wizard will take care of it.
1. Click Start
2. Select All Programs
3. Select Accessories
4. Select System Tools
5. Click Disk Cleanup
6. Disk Cleanup will do its calculations
7. From the Drives list in the Select Drive dialog box, select the hard drive that contains the Msocache folder
8. More calculations
9. Select the Office Setup Files checkbox in the Files to Delete list
10. Click OK
11. When you are asked Are you sure you want to delete these files? select Yes
You can prevent it from being place on your drive in the first place by selecting Delete installation files check box during the installation of office from the CD