Disk Write Protection in Windows 10 keeps re-setting

I use two external Western Digital HDD disks (M & N) as part of my back up routine.



Almost every time I try and run backups now, I get an error message telling me that Disk N is read only. I'm quite happy resetting this using Diskpart, and it works every time.

However, I'd like to find out why it keeps re-setting (and why N is always the one to re-set, but M has never done this.)

I've tried searching but got plenty of hits on how to resolve it but not on how to stop it happening. Can anyon etell me what causes this.

Thanks

I am having a similar problem. Not only my external drives but all USB flash drives.
I have tried several things and none have stuck.
Modifying the registry helps for one back up but the next time it did not work again.
If I had to guess, it seems like each time Windows does an update I lose external drive access again.