WP7: "The app could not be launched for debugging", different from the usual

I have joined the legions of people getting the error "The application could not be launched for debugging. Ensure that the target device screen is unlocked and that the application is installed."

My symptoms are different from usual, and the usual fixes don't work.

I can:

* deploy to the emulator

* run on the emulator

* debug on the emulator

* deploy on the phone

* run on the phone

I cannot:

* debug on the phone.

Attempts to start the debugger on the phone (F5 from VS) will recompile my app (if necessary), deploy it to the phone, and then raise the above error.

Yes, the "Build" and "Deploy" boxes are checked in Configuration Manager. Yes, it has an appropriate SplashScreenImage.jpg Yes, the phone is dev-unlocked, and pin-unlocked.

Update 1:

Unregistering and reregistering the device didn't help.

But the problem is device-specific -- it doesn't happen on a different phone.

If no other solution turns up, I'll probably reset the phone to factory original and start over.

Update 2:

I have two phones and two development systems. Three of the four combinations work great; it's only one phone on one dev system. Resetting the phone to fac开发者_StackOverflow社区tory condition didn't help.

Any ideas?

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Have you tried using the WP Connect tool instead of using Zune?, I have had a few occasions where Zune does not see the phone properly or the device link registration was invalid (also try telling Zune to forget the particular device in the settings)

In any case using the WP connect tool (without Zune running) has usually worked for me in these cases.