Can't open deck after update

I installed an update today on my desktop version and now when I try and open it, I get the following error:

“This profile requires a newer version of Anki to open. Did you forget to use the Downgrade button prior to switching Anki versions?”

When I click ‘OK’ it brings up the profile window.
I just have one profile.
when I click ‘downgrade and quit’, I get the following error: “The following profiles could not be downgraded: myprofile”

I have read some of the forums that say you need to switch profiles. When I click on the anki tab in my top menu bar the only things that come up in the drop down menu are ‘services, hide anki, hide other and quit anki’. I can’t access files, help etc.

How do I fix this and get back to the way things were??! I should have never updated in the first place.

That indicates you have an older version of Anki lying around, which you opened after opening the newer version. If you open the latest version again, you should find your profile can be loaded correctly.