Why doesn't my home button work anymore?

[AC Question]

Hello, 1 or 2 weeks ago, I updated my nexus 5 to android Marshmallow 6.0 through OTA. Eveything was working fine until today, The device rebooted by itself and I lost access to my quick settings through notification and the home button became useless, it doesn't do anything when I click it but if I hold it, Google Now on Tap works fine. When I opened a guest account, everything worked fine. After returning to the main user, quick settings was working again but the home button still doesn't work. What is the solution?

 

[B. Diddy]

Welcome to Android Central! Try wiping the cache partition, which can take around 5 minutes on a Nexus 5: http://forums.androidcentral.com/nexus-5-rooting-roms-hacks/352008-guide-nexus-5-recovery.html. If that doesn't help, see if it persists in Safe Mode: https://support.google.com/nexus/answer/2852139?hl=en