GDIVE Mobile USB corrupting files

I have this external drive for over two years and so far it has worked perfectly well and then suddenly files started to get corrupted with a read error.
I tried to backup my date on other discs onmy to find out that a good number of files were actually also affected.
I’m trying to recover that disc but I dont know how. The Disk Utility on my Imac is is not allowing me to dismount or mount or partition. What can I do?

With corruption the best way to attempt a repair is with some powerful 3rd party software such as Disk Warrior. The built in First Aid is unfortunately quite week in the Mac OS.