Contact sync with Google cannot create or update a folder ("Cannot create a system group")

I was successfully updating contacts in eM Client and sync was working perfectly with Google Contacts. And then I started getting an error message about “Creating or updating a folder” which stated that the execution failed because it “Cannot create a system group.” I now get this error message each time I change any aspect of any contact, and sync no longer works.

I’ve tried deleting the offending folder (which is named in the error message), however it reappears immediately with the next attempted (and failed) sync.

At the same time, my main Contacts label in Google only lists 8 of my contacts, when it used to list all of them (several hundred). Each of these contacts is still available under the labels I’ve created, but I can no longer see all of them in the consolidated Contacts list.

Remove the account from eM Client, then add it again.