"ID10T" wrote...
We are have tried both XLS and XLSX

If he's saving to XLSX, and the XLSX file also loses formatting, then it
shouldn't be due to macros since XLSX file (in theory) shouldn't be able to
save VBA modules. In that case, if the user's lost formatting may actually
be a true bug in Excel itself.

Last thing I can think to try would be saving the file TWICE, to different
drives, using a different filename for the second save. After the second
save, the open file should still show the user's formatting. Open the file
it was first saved as. Does that file still have the user's formatting? If
so. exit Excel, relaunch Excel and open each of the saved files. Do they
still show the user's formatting?

If the file saved first opens without the user's formatting, close it and
copy the second saved file (still open in Excel, so you many need to use a
console window to do that using a command prompt copy command) to the first
file, overwriting it. Then open that file again. If it's still lacking the
user's formatting, then it'd appear Excel isn't saving the user's formatting
when it saves the file, and that's seem to be a bug in Excel.

The last possibility I can think of is that the user's formatting could be
conditional formatting that's triggered by a formula that relies on state
information that's TRUE when the user creates the formatting but FALSE when
the user reopens the files. So is the lost formatting simple formatting or
conditional formatting?