Today I had a problem and I have no idea how it started - maybe the patch that was the part of Windows Updates - who knows. The problem was that the session files were created as read-only. Subsequently they could not be written to and web applications were reporting an error like this:
[14-Nov-2008 16:45:51] PHP Warning: Unknown: open(X:\folder\sessions\sess_ec6268fc01eaebb89eb0ea6bdbeae6a8, O_RDWR) failed: Permission denied (13) in Unknown on line 0
I tried many things settings permissions, ownership of the folder etc. I tried to give IUSR_Computer user full access to the session directory, ownership - none worked. I already experienced similar problem before and decided to remove all other rights on that particular folder - especially Creator Owner and IUSR_Computer. The only rights I left were: Everyone and System both with Full Control. This seems to work for now.