i've started to use keywords. Also i export all files back to the XMP-Format. On some files the changes are not permanent/lasting.
My smart-collection tells me 5 seconds later that the meta-data should be saved again..
Do you have any suggestions?
Yes, there are lots of issues like this. Mostly I find that closing the catalog and opening it will solve the problem, or you can read the metadata from the files after saving them. It seems to be a problem that Adobe cannot or will not fix.
and others that I think you can find yourself