Screen goes black when making calls

[Beauty24]

Every since the latest update my Sony Xperia z ultra screen goes black when making calls. How can this be fixed. Everything else works fine on my phone. I have no screen protector.

[Uliwooly]

Settings > about phone > diagnostics > test > test proximity sensor. Also, test it in >>> safe mode

[Beauty24]

I know for a fact it's nothing to do with anything I installed. I rebooted the phone to factory settings so this is not the answer. Nothing wrong with the sensor. It has to do with the new update.

[YoGem]

Did you perform a factory reset? If the software update is at fault a factory reset may not fix the issue, can you try as uliwooly said in safe mode and eventually trying after a software repair?

[YoGem]

Just to clarify, a software repair is more than a factory reset, it erase all previous settings and reinstall a fresh copy of the os that should be, at this point, worry and bug free.

If after a software repair the issue persist then you can contact local support or inform Sony about the issue, they may verify and eventually release a bug fix. 

[Beauty24]

I have done a software repair and it does nothing. Also tested proximity sensors. It passed. It was an update the screwed my phone.

[Uliwooly]

Contact your Local support to get the phone inspected.

[andyjalanajalan]

You can do nothing. It's a long time unfixed bug

[Richtech]

I have this problem on a mates phone, took the back off, and when you gently press down on the motherboard where the sensor is, it works. A hair width too far from the screen with the new software update. So im working on a fix....no apps work, this sensor is either on or off so cant be calibrated, but if I can get the sensor closer to the screen it will work