The MSOCache is a file used to install MS Office. In fact it allows the installation of additional options without the Microsoft Office installation CD-ROM. It is possible to remove this file using the default Disk Cleanup
tool provided with Windows:
- Click on Start> All Programs> Accessories> System Tools> Disk Cleanup
- Select the drive containing the MSOCACHE directory.
- In the list of files to delete, select Office Setup Files
- Confirm by clicking OK.
More information on http://support.microsoft.com/default.aspx?kbid=825933