We have an issue that just developed. I have several Windows XP computers and two Windows 7 Professional laptops. All were working fine editing and saving files to our Window NT server. Now we get a "Document not saved" message. There is a file created, but it has "0" bytes and cannot be opened. The message states that MS Excel cannot open that file becuase it is not a valid "xlsx file. I have run virus scans on all of the coputer using Kaspersky Internet Security 2010. Found some minor bugs that were removed. Files can be saved to individual hard drives and then they can be cut and pasted to the server. I thought the permissions may have gotten changed on th eserver, but I reset those.