G-Drive Pro Thunderbolt (1) causing iMac to crash after Catalina update

After updating to Catalina on my late 2013 iMAC Random shutdowns ensued when my Thunderbolt external drives were mounted. Tried various fixes, clean install, fresh backups, many calls to Apple Support… eventually bringing the iMac into my Apple Service Provider, along with the external hard drives I used for backups, both of which were connected via the Thunderbolt 1 interface. They rebuilt (as it were… cleaned up) the iMac Fusion Drive, redid the clean install, and tested both external hard drives, reformatting one of them (at some cost). They could find no hardware issues with the iMac.

Random shutdowns occurred only when Thunderbolt external hard drives were mounted. So replaced with new USB external drives… no more shutdowns. I retired the one WD T-drive and Griffin replaced the G-Drive Pro along with a new Thunderbolt cable under warranty. However, random shutdowns (crashes) persist… only when the G-Drive is mounted, not when the USB external drives are mounted. This is after even a very new clean install, and migrating over only User Data, no Applications or Network settings from the latest TM backup.

I have a feeling Catalina is not playing nice with the Thunderbolt interface (yes, we’ve done all the PRAM and such resets)… hardware? But problem occurred only with Catalina install.

Any opinions are welcome!

Yea, with every new macOS update there seems to be more issues. And Thunderbolt has never been a friend to them! (Which is unfortunate because I love its speed!)

I’ve had an iMac Pro since late 2017. Only recently since Catalina I’ve been getting the error “Your computer restarted because of a problem” – only when I reboot. And only when the drives are connected, it seems.

Apple suggests what you’ve done - erase and install - which I’m not convinced of. Just wanted to circle back to these forums if there were any known issues here that were drive-related.

Thanks for the report…

I have an Mac Book Pro (2012) updated to Catalina and that was no improvement (need to be polite to Apple).
So I will wait to update my other Macs.