Does Postbox have files named msgFilterRules.dat in its profile, i.e. in the folders that contain the data for each account? In TB such folders are e.g. ImapMail/imap.gmail.com or Mail/pop.mail.yahoo.com.

Thanks a lot. Yes there are files named msgFilterRules.dat in the various folders corresponding to the various accounts. I copied them in the relevant folders of TB. The list of filter names appear in TB but when I try to open a filter I get an alert saying that the program cannot understand it.

The .dat files can be opened in a text editor, and the ones in TB that don't have any rules have this:

version="9" logging="no"

so I suggest you look at the ones in Postbox to see if they have something different that might make them incompatible.

Thanks a lot. The .dat fils in Postbox (and consequently those I copied to TB) all have version="9" logging="no" Should I replace the above by something else in TB?

No, if the Postbox 'header' is the same as the one in TB, I can't say why the Postbox files that replace the TB files aren't viewable in TB in Tools/Message Filters. Check that when you copied the Postbox files to the TB profile, overwriting the existing files, TB was closed.

Yes, it was closed.