When I open an existing PowerPoint file from a folder on the desktop, I get the following error when I do File > Save As, and try to overwrite the existing file (this typically starts happening after you have previously saved > overwrote three times or so without error:) "There was an error accessing ComputerName/Users:usernamedesktop:filename.ppt" After encountering the above message, my next step is to try using the regular "save" command, which this message: "This is a Read-Only file. Do You Want to Save it Under a Different Name?" If I close the file, re-open, and restrict myself to only using the "save" option, then the error message will never make an appearance, which is fine- except in cases where I want to overwrite an older version of the file that is stored on an external hard drive; in that case I have to update the file locally first, then manually overwrite the other copy, which gets annoying :) So basically it seems that Powerpoint starts treating the file as "read-only" after saving over itself about three or so times. He is where it gets complicated: These files originally existed in my local login profile (on the desktop), until they had to be moved to my new profile that created for my network login account (joined to a domain.) On this particular folder, I did have to re-take ownership of the folder containing the powerpoint files, but permissions should be correct now (I am the owner of the folder + contents and have read/write access to all, and am also an administrator on the laptop.) In addition, Filevault encryption is enabled for my account, which was done shortly after the laptop was connected to the domain. Conversely, I also store a few powerpoint files in a folder on the root of the Mac HD, of which I am also the owner. In comparison to the folder of powerpoint files on the desktop, the powerpoint files in this folder do not encounter the above error messages and can overwrite older versions in different directories without a problem. As far as permissions go, both folders appear to be set identically. Finally, I tried using the Mac Disk Diagnostic tool and verified permissions for the entire drive, which did not find any inconsistencies in those particular folders (it did gripe about some temp folder and fixed the permissions accordingly.) Any ideas as to what's causing the error message?