Info Today I discovered the 'OfficeFileCache' folder...

mikeymikec

Lifer
May 19, 2011
17,717
9,603
136
Office 365, %localappdata%\Microsoft\Office\16.0\OfficeFileCache\0\0 contains over 100k files in 604 folders totalling ~1.8GB, each folder with spurious names.

The only reason I discovered this was that I'm doing a more-thorough-than-usual backup of a customer's user profile and it is taking freaking ages to copy this particular folder structure to a HDD via USB 3.0.

So many questions. LibreOffice apparently has no cache folder (why would an office program need one?). My Firefox cache folder for multiple Firefox profiles only contains ~3k items and weighs 1.2GB. Why create a folder structure in the cache folder which starts with one folder inside another, each named '0'? Why does MS love CLSID-style spurious folder names?
 

mpo

Senior member
Jan 8, 2010
457
51
91
Open Word. Go to File -> Options (all the way at the bottom) -> Save -> Cache Settings.

You can clear cached files there.
1682343698372.png

I suspect MS created common location for integration with OneDrive, Sharepoint, and other Office components.
 

mikeymikec

Lifer
May 19, 2011
17,717
9,603
136
Open Word. Go to File -> Options (all the way at the bottom) -> Save -> Cache Settings.

You can clear cached files there.
View attachment 79887

I suspect MS created common location for integration with OneDrive, Sharepoint, and other Office components.
Interesting, but I wonder if that's what was in that folder structure; at a glance I saw lots of files going by that were less than a kilobyte in size. Perhaps the uncompressed contents of the OpenXML format documents get dropped in there? I could easily see a stylesheet (assuming that format uses them) weighing <1KB. OpenDocument format is similar in its compressed nature though yet no LO cache. Perhaps it's just for docs in remote locations (though e.g. OneDrive will download a file in its entirety when the user requests it)?