I built an Android app and tested it on API 2.3, 4.0 and 4.0.3. It worked fine in the emulators (including different screen resolutions.)
Then I decided to give it a go on my Samsung Galaxy Nexus (4.0.2, factory unlocked, stock ROM).
I installed the Samsung USB drivers (Samsung_USB_Driver_for_Moblie_Phones_v1_4_6_0.exe), used the Titanium Community Developer to run on device.
As soon as the app went on the phone, it displayed "Unfortunately, Launcher has stopped.". If you click ok, it comes back up after 2 seconds… I tried all sorts of app removers and cache clears, but they all crash when they try and look at the app that was installed on my phone.
Its an absolute nightmare, looking like my only option is to factory reset… this would mean downloading all my apps and music (Google music) again :(