Sansa Clip Zip - Suddenly only boots in standard Clip Zip interface

[greenman]

Sansa Clip Zip 4GB
Sansa Firmware Version 01.01.17A
Rockbox Utility Version 1.4.0
Rockbox Firmware Version
USB set to MSC
1.73GB free of 3.65GB available
Windows 10

It suddenly one day stopped booting into rockbox like normal. It will only boot the standard Clip Zip interface, which is disappointing compared to Rockbox.

I tried uninstalling Rockbox, reinstalling an earlier version of the Sansa Clip Zip firmware (hence 17A).
After attempting to uninstall/reinstall with the Rockbox install Utility, I decided to go manual.

I now seem unable to make any changes to the internal memory.
I can't manually drag and drop .rockbox into the This PC\Sansa Clip Zip 4GB\Internal Memory folder from my downloads folder.

I tried creating a new folder in the This PC\Sansa Clip Zip 4GB\Internal Memory folder
This is the warning I got:

"The new folder could not be created in this location.
The device has either stopped responding or has been disconnected."

But it's not disconnected.

I'd be grateful for suggestions in recipe format as to how to proceed.