I'm experiencing weird behaviour with my iPhone CI job (running in TeamCity). Every once in a while our build fails without any indicative error in the build log. The build reaches the last stage of codesign validation and I get `** BUILD FAILED **` message immediately after.

These are the last lines of the log of a good and bad builds -

```
Bad Build
[15:00:56] :             [CodeSign]     /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/Validation /Library/TeamCity/buildAgent/work/dc055fa257f562be/DerivedData/MyProject/Build/Products/AdHoc-iphoneos/MyProject.app
[15:00:58]W:     [Step 3/6] ** BUILD FAILED **

Good Build
[14:09:13] :             [CodeSign]     /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/Validation /Library/TeamCity/buildAgent/work/dc055fa257f562be/DerivedData/MyProject/Build/Products/AdHoc-iphoneos/MyProject.app
[14:09:13] :     [Step 3/6] ** BUILD SUCCEEDED **

```

Because it's running in a CI I looked for user interaction problems (opening the keychain...etc') but usually xcodebuild spews the relevant errors.

Is there any other log I can dig into to find the cause of the build failures?

EDIT:
Seems I had the same problem like [build failed jenkins iOS no error](https://stackoverflow.com/questions/19506982/build-failed-jenkins-ios-no-error).