I've been wrestling with this, cross-platform. At work (a non-profit on a lean budget), I use FMP 5.5 on Windows XP. At home, I have FMP 4.01 on Mac OS 9.1, on a G3. Both are registered, paid-for versions, but I can't take my work database home and work with it on my Mac, regardless of how I save it (.fp5, .fp3, or .fm).
The only option I haven't tried is a tst export, but since there are about 80 fields, that could be a lot of work, and I need to do it several times a week. (This isn't complex data -- just text and number fields. It's a data-base of donors and gift histories.)
One thought is to persuade my bosses to upgrade to FMP 6.0, but it's $150 and it will have to work . Will FMP 6.0 for the PC allow me to save a file in FMP 4.01 for the Mac? It seems so simple.
(I'm not going to be able to persuade them to upgrade my home Mac version.)
Any suggestions would be appreciated.