Since last night, when I open Sonar Pro I get a Cakewalk advertisement instead of my start screen.
 
Why? How do I get my start screen back?
 
Sonar Professional 21.7.00 BUILD 18 Hopkinton.
 
Thank you?
Jeffrey Pike

What happens if you choose:
file --> start screen
?

Does the problem go away after applying the Kingston update?

@THambrecht: Same thing.
 
@scook: Perhaps I am not authorized to install the Kingston update. Despite Command Center showing all green, Help -> About Sonar... says I'm on Hopkinton. It also says my membership ended 9/14/2016. My suspicion is that Cakewalk is trying to force me to upgrade (also assumed, not for free) by taking away essential functionality in the program I paid for. Is that too harsh?

Hah! If I disable my network card, I get the normal start screen.

If you had a membership though Sept 2016, that is a year past Hopkinton which was released in Aug 2015. It seems you may be running on the version you originally purchased. My guess is your Command Center is old too and not showing correct information. Update the Command Center.
 
If I were to guess what has happened is SONAR managed to slip into demo mode by mistake. Since the version is 2 years old, the demo has expired. Updating the Command Center and SONAR may fix the problem. If not you should contact Activation Support.

jeffikonian
Hah! If I disable my network card, I get the normal start screen.

This is forcing the start screen to local operation. I still think you should consider updating SONAR. If the About screen shows Hopkinton and the membership lapsed a year later, there are several updates not applied to SONAR.

jeffikonian
 My suspicion is that Cakewalk is trying to force me to upgrade (also assumed, not for free) by taking away essential functionality in the program I paid for. Is that too harsh?

I think your being a wee bit paranoid man.
Its all good. Just update to as far as you paid for and you should be fine.
Listen to Scook and his advise.
Good luck

I reinstalled Command Center. It says I am on the current version of Sonar, 2016.08 (22.8.0.030). If I right click the Sonar Professional link in Command Center under "Connected Products", I see I can roll back to earlier updates. There are a dozen updates listed there after the Hopkinton update, which I assume means that I did install all of those updates. I rolled back to the last version on that list, 2016.07 (22.7.0.41), and when I checked Command Center again, it was telling me to update to 2016.08 (22.8.0.030). Which I did, but in Sonar, Help -> About SONAR... still says I'm on Hopkinton. Do you think Activation Support is my best bet going forward?

What does it say in the About Box (Help -> About)?