It doesn't seem to be an issue when there is a mobile account set up on computer. It seems to strictly be related to user's network home folders. I have also noticed the time factor involved where if you wait 30 seconds or so, the powerpoint will open correctly as read/write. I have a couple theories. The first is that it has to do with the temporary files that MS Office put's in place on a user's network home folder when they launch Word/Excel/Powerpoint. I don't believe the permissions are a problem since my permissions are set correctly and if they weren't why would I get varying results for the same document and the same user. Do you use NHR (Network Home Redirect) at all? My other idea involves NHR which I have installed on about 70% of my mac clients. I don't actually believe this is the problem since NHR is actually designed to fix this type of issue but I could be wrong. By the way, I'm running a OS X server 10.4 where all my user's home folders are stored. 85% of my client Mac's are 10.5, the rest are 10.4.
