PS:

looking at Steve Bell's reply to a similar issue below, I can confirm....

Recycle Bin is empty
Temporary Internet Files is empty
no ng messages etc

No custom number formats (all standard options)
Very few formats/fonts throughout (this is a "data table" with very little
formatting)

No Code Module/Macro names the same
No reserves names used (to my knowledge, and crashes when disabled anyway)
No variables double-declared (nearest we have is a public Dim and a ReDim in
a sub)
No macros with the same name.
Option explicit used as standard

Unfortunately I can't use code cleaner, and I'm relying on memory for
everything that might be in there, as I can't open it to check!

I expect it's probably a corruption, but not sure why, and would obviously
like to avoid this in future if at all possible, so any ideas as to what
would cause that would also be appreciated.

Thanks
DS