Problems capturing with a third party device?

I purchased a Sony GV-D800E Video Walkman PAL after asking other users if it will work in FCP 6. I want to use it to capture Digital 8 tapes. When I've used the Sony DCR-TRV330 camera, I recorded these tapes on it worked fine when capturing them in FCP 6 .The answers about the GV-D800E I received were all positive but when I go to log and capture FCP just crashes. The only thing different is when I was using the Sony Camera, I was using a Mac with a FireWire port. Now I'm using a Thunderbolt to FireWire adaptor.
This deck works with Adobe Premiere 12.0 just fine, so why wouldn't this deck capture in FCP 6 when a camera from the same era does?

Any help or advice would be greatly appreciated!

I think the adapter may be the issue, but I'm not positive about that. I have the same (US version) and in FCPX it works fine with a direct link to the firewire port on our mid 2010 mac pro tower. I don't believe I ever tried it in FCP 6. You might try to see if Quicktime recognizes it by choosing to do a new movie recording. The unit has an iLink control setting, which maybe you can also try to set to see if the adapter prefers it one way or the other (or if FCP 6 is finicky about that).

Cheers for that Mate. I'll give you advice a try and see where that takes me. I've yet to take the plunge with Final Cut X so I think its time I start. I've got hundreds of tapes to capture so it wouldn't take much to get up to speed on the capturing process in FCX. I got it with my 2013 iMac, is it a pretty stable bug free platform?

FCPX is very stable with Sierra and El Capitan OS. There are still quite a few bugs when used on High Sierra, mostly related to third party plugins, but also some FCPX quirks.