I have a Lumia 920 with all the latest OS updates.
When I make or recieve a call the screen goes blank (black) and I can't access the OS. Extremely embarassing when I hit someone's voicemail and have to leave a three minute message of me trying to hang up.
When I press the middle button to activate the screen, the controls flash up for a second then disappear.
I only regain control over the phone when the call ends.
2013-03-21 5:26 - edited 2013-03-21 5:27
If the problem is related to the Proximity Sensor getting blocked by a screen protector or the Dust issue then try the suggestion posted in this thread ..