I think my problem is similar to this post from 2014:
My Passport Ultra - data cannot be access after wake up from default sleep timer (this user never got an answer).
I have a My Passport Ultra (USB C) 1TB drive that I’ve had for a while but haven’t used much. I’m trying to set up a backup schedule with my two Windows 7 SP1 64-bit PCs. After the drive has been idle for a while, it locks up - I can still see the drive in Windows Explorer, but if I attempt to add a folder in Explorer, Explorer freezes and won’t unfreeze until I physically disconnect the drive. If I attempt to start a backup using Macrium Reflect 7 Free, then it freezes, similarly. In both cases, I can’t close the frozen window, and I can’t terminate the explorer.exe process or one of the Macrium processes (and the others restart after I stop them), using Task Manager.
Everything is back to normal after I unplug and replug the Passport drive back in. I think I’m using a USB3 port on the laptop, but it’s Windows 7, so there might not be USB3 support and the connection might actually be USB2.
This is a problem for scheduling backups. Is the only solution to install the Utilities and turn off the sleep timer?