G-Drive firewire only mounts one partition?

Need help here please?

I’ve been using 2 G-Tech 4 TB external hard drives -both partitioned into 2 tb per HDD and now only one partition mounts from one drive, my Time Machine and the other with all my data, photos won’t mount? Ran disk first aid numerous times on both computers but got A FILE EXIT CODE IS 8? is my partition gone for good? is this a hardware or software problem?

The fact that one drive mounts makes me hopeful. Any advice would be greatly appreciated.

If it is just a partition then it is corruption and your best option at being able to recover/rebuild it is to use 3rd party software such as Disk Warrior. It is much more powerful version of First Aid which essentially never works.

Thank you. Will this repair the partition with the data intact? Does Disk Warrior cost a lot? Thanks!