MSO Cache, aka 'Local install source' folder is empty until you try to install office applications from a CD. When you insert the office CD in to the device, system will check for the free space drive. If it finds any drive containing at leaset 1.5 GB free space, install source files are copied to this folder. These files are used when you click on the 'repair' option on the 'Add/Remove' control panel module and service pack updates.
Deleting the MSO Cache files:
Do not delete the 'MSo Cache' folder directly.
- While installing office:
check the 'delete installation files' check box before clicking the 'finish'.
- Any time After installing office"
Open the 'Disk Cleanup' tool located at :
start -> All programs -> Accessories -> System Tools
Check the 'Office setup files' check box and click to delete.