Ever since I updated my MacBook to the last macOS Big Sur, I have been unable to access any of my external hard drives. I’m sure the issue isn’t on the USB cable because I used them fine on other non-Apple computers. Rebooting, changing Finder settings, or running First Aid had no use. One thing peculiar is that I get a folder named Relocated Items on the desktop after the update. Does it have something to do with my drive not showing up? Or is it due to certain bugs?
It’s unlikely that the “Relocated Items” folder is related to your external hard drive not showing up on Mac. I think it’s either due to bugs, incompatibility, or disk issues, though it doesn’t make much sense that all of your drives could have issues simultaneously.
Is your external hard drive appearing at Disk Utility? If it is, it should only be a software issue rather than a fatal hardware problem.
I suggest you check if your drive shows up in this data recovery software: iBoysoft Data Recovery for Mac. It’s free to check and preview your files.
If it detects your drive, recovering your data and reformating the drive is probably the fastest way to get your drive accessible again.
Have you tried macOS Safe Mode? It’s a troubleshooting mode that isolates third-party software or other processes that may be preventing your external hard drive from being mounted on a Mac.
See if your external disk shows up in Safe Mode. If it does, try looking for the app or process that may be responsible for it.