A valid provisioning profile for this executable was not found... (again)

If none of above stated works then check for your device date, make sure your device date doesn't exceed profile expiry date i.e. not set to far future.

+1 to banging my head against the wall for a day or two...

Also check this setting:

Build Settings -> Code Signing -> Provisioning Profile

After following the above steps, "Automatic" setting worked for me. ~kjm~

File > Workspace Settings > Set Build system to "Legacy Build System"

This happened to me yesterday. What happened was that when I added the device Xcode included it in the wrong profile by default. This is easier to fix now that Apple has updated the provisioning portal:

1. Log in to developer.apple.com/ios and click Certificates, Identifiers & Profiles
2. Click devices and make sure that the device in question is listed
3. Click provisioning profiles > All and select the one you want to use
4. Click the edit button
5. You will see another devices list which also has a label which will probably say "3 of 4 devices selected" or something of that nature.
6. Check the select all box or scroll through the list and check the device. If your device was unchecked, this is your problem.
7. Click "Generate"
8. DON'T hit Download & Install – while this will work it's likely to screw up your project file if you've already installed the provisioning profile (see this question for more info).
9. Open Xcode, open the Organizer, switch to the Devices tab, and hit the Refresh button in the lower right corner. This will pull in the changes to the provisioning profile.

Now it should work.