Enter Coherence greyed out

I just updated to version 12 and now find Enter Coherence unavailable. Parallels help at kb.parallels.com suggests a device driver problem, but mine appears to be as it should - Parallels Display Adapter (WDDM) is installed. I went so far as to uninstall, then reinstall, but still no Coherence mode. Is there another solution?

 

Hello JamesM6,
Please reinstall Parallels Tools and check how it goes!

 

There's a problem... Parallel Tools isn't showing up as installed. How do I fix that?

 

Hello @JamesM6
Did you try this solution?

 

I had not, but Option Three worked! So I've got Coherence back. Thanks!

 

Glad to hear that, @JamesM6