MS renames xlsx as xls in quarantine?

[Garry Glendown]

Hi,

I've set up a script to download quarantined attachments, which works
fine ... anyway, I came across a problem recently which I can't really
find a reason for ...
A mail attachment was received with an .xlsx file, which was
quarantined. Anyway, the original filename wasn't kept, but rather
renamed to .xls, which can mess up certain Excel versions when loading
(Excel 2010 will load it none the less, albeit with a warning).
I was trying to find some sort of setting that may have caused this
behavior, but couldn't see anything in the filename rules etc ...

Any idea what's going wrong?

Thanks, Garry