Bob,
Thanks for the reply! Yes, the table did have an existing .CDX. I don't need a temporary tag, actually, I was just experimenting and ran across this behavior.

Mark

>>Can someone please explain these results:
>>
>>1) Open two VFP 5.0 sessions on the same machine.
>>2) SET EXCLUSIVE OFF, on both.
>>3) USE MyTable (any FREE table), in both sessions (same table used).
>>4) In one session, do an INDEX ON Expr TAG Expr - no problem.
>
>This is your downfall. did the file have a .CDX originally? If you want to use and index on the fly, create a .IDX on the machine that is going to use it, then erase it. You can add tags the a file that is opened shared, since it will LOCK the file.
>
>BOb