My Cloud Back Job up to My Passport USB Failed

Cannot backup My Cloud to My Passport USB.
Message:
The backup destination folder is read only. Please check and correct the setting.
My Cloud firmware up to date 5.19.117
My Passport when connected direct to PC is not read only. Can copy to it no problem.
Format is NFTS
Advice appreciated please.

@grecian17
Have you looked at the User Manual, Chapter 12?
My Cloud Personal Storage User Manual (wdc.com)

You may need to check the OS5 Online User Manual too.

Thanks for that. Issue seems to have been disconnecting USB drive without using “Eject USB drive” (top of Dashboard Screen). Then replacing with another USB drive with different spec.