When you save a file, excel will save it as a temporary file (8 characters, no
extension). Then if that save is successful, excel will delete the original and
rename this funny named file to the original's name.
You see the results when something interferes with this process.
A couple of things that get pointed at are antivirus software and network
problems (hardware or permissions).
Since you just migrated, I'd start looking at the network side.
But if that didn't fix it, maybe you could disable the antivirus software
(temporarily) to see if that
helped.
(if the problem went away by disabling the AV software, maybe a visit to its
site to see if there are any upgrades available???)
