The main disk space usage is due to 2 places which cache install information, these are: 1) MSOCache, which is almost a complete copy of the install files, which contains the data for parts of the suite you haven't installed too (in my case, Outlook is stored here, even though I don't have it installed) 2) Service pack MSP/MSI packages in the Installer folder (the Office 2007 SP2 MSP is 327mb! In total, mine come to 387mb For me, the usage in MSOCache for the standard edition of Office 2007 (Word, Excel, PowerPoint, Outlook) is 300mb. Altogether, the cached files amount to approximately 700mb For office 2003, I read that you could remove the MSOCache folder, but you'll likely run into problems by removing the folder for 2007, as I did. If you did delete the source MSOCache folder & Installer files, I think you'd also have problems upgrading the suite to any later service pack, and the same might apply with hotfixes... FYI, it is worth looking at this post, which has a guide on administrative installs etc: http://www.msfn.org/board/index.php?s=&...st&p=493938