NO Laptop backup after OS5 upgrade

I have just updated the my PR4100 to OS5. Everything seemed to worked with the install.

However after a day or do I noticed that my laptop files were not being backed up.

My WD sync says “MyCloudPR4100 is missing”

I’ve since read that WD sync no longer works with this new OS5

At no point did the upgrade warn me my working backup system would become worthless.

What have WD frigging done- I had a perfect working, albeit simple laptop back up and my phone for photos.

Is there a way to simply go back to OS3 or a simple way to restore my laptop to back up files.