Hi, David,
of course QuarkXPress files are cross platform with the usual suspects (fonts, a few graphic formats etc.)
As Windows expects file extensions, please make sure that you add a .qxp to the filename.
Secondly, for downsaving to work correctly, you shoudl always use the latest subversion of each program, e.g. QuarkXPress 7.5 (and not 7.31) to open a downsaved QXP8 file and QuarkXPress 6.52 (not 6.1 or 6.5) to open the downsaved QXP7 file.
Then it should work.
Best
Matthias
Matthias Günther
Senior Product Manager
Quark Software Inc.(Please note: As I am traveling frequently, answering your post might sometimes take longer)
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