Back Button not working after Marshmallow Update

[BryanP]

My phone recently updated to Marshmallow. After a couple of days the back button stopped working. Other than that my phone is working fine. Has anyone else had this experience too? Any suggesition for a fix? Phone is in very good condition, no cracks on screen and I didn't drop it. Thank you!

[Uliwooly]

@BryanP

settings > about phone > diagnostics > test > test the touchscreen and also test it in >>> safe mode

[BryanP]

Thanks. I've already done both. The touchscreen test was a Pass. On Safe Mode, the back button is still not working, that's why I thought it has something to do with the Marshmallow upgrade

[Jake-SonyXperia]

Hi BryanP,

Welcome to the community,

Based on this information, I would suggest backing up your device and performing a software repair to see if this helps resolve it.

Backup

Software Repair

[BryanP]

Thank you Jake. My situation got worse. Now my Home and Recents button also stopped working, I can't pull down the notifications bar, and the letters 'C' and 'F' on my keyboard no longer function! Though I can pull down the notifications bar when my screen is locked - very weird! So I backed up my phone and did a software repair, but still nothing worked! I'm thinking of sending it to Sony to fix unless there's any other suggestions please for a fix? In the meantime I installed an app so I can have a Home, Back, and Recents functions and can pull down the notification bar on an unlocked screen. Thank you!