I had the same issue. After updating Chrome x64, I decided to update Chrome Canary x64 too. Since the auto-update from the About page failed, I ran the new installer manually and it succeeded. On the About page I saw I have the new version, but it still showed the same error. Then I noticed that 3-4 processes from Google update service are running as a Scheduled Task. I tried to stop the task, but this had no effect.
This solved my issue:
Finally I used End process tree from Process Explorer. Now the About page is showing: Google Chrome is up to date. :)