Ok well this is crazy, but I had been doing a query for the logical name and filename. They all were named after the DB, but apparently the previous DBA had the logical and physical names for DB A swapped with an offline DB B.

DB A --> BDat.mdf D:\BDat.mdf

DB B --> ADat.mdf D:\ADat.mdf

So I would take A offline, B already was but when trying to swap the file on A it was actually B that was in the wrong place which is why it didn't work.

If that makes sense.

In any case the

USE FOO

EXEC sp_helpfile

returned the other DB name and I realized what was going on.

Thanks!