I have seen problems with various McAfee setups and versions. You really do need the latest version and sometimes the Screen Scan causes this problem. I have also seen it when all of the settins are set on to scan for viruses in everything. They are taking a toll on the processor and then the system is getting timeout errors when trying to read off the network or a slow hard drive. I have even seen it cause read errors in spreadsheets and word processing files across a network at client sites.
