I was notified my avast had a update so I decided to update it. When it was done updating it asked me to restart my computer so I did. After relogging into my account windows defender had dissapeared. I restarted again and I saw it when my icon were loading but then it went away. Anyone have the same problem or have a solution?
When you install a antivirus program, Windows defender is auto disabled
Hi. I have been using avast for a while and it always showed the windows defender Icon when i opened system tray so I wasn’t sure. Thanks
Happened to me also,logged out and back in and reappeared 
If you’re using windows 10, the windows ‘defender’ icon is by default, hidden, so, by clicking the ^ in the task bar, it should show you the shield with a green check mark in it, or alternatively, you can show that icon by right clicking the task bar, then going to ‘Taskbar Settings’ then scroll and click the link ‘Select which icons appear on the taskbar’ and here you can either have ‘all’ icons show by clicking the switch at the top to ‘On’ or scrolling until you find ‘Windows defender notification icon’ and click to ‘On’ this will show defender icon all the time in the taskbar, but sometimes, a windows update will overwrite this setting and it will need to be re-enabled again.
Windows Defender Security Center Icon in system tray: (Not Windows Defender Antivirus Icon)
https://screencast-o-matic.com/screenshots/u/Lh/1546887601003-66150.png
Windows Defender is visible in my sys. tray along with Avast.
I’m not running Windows Defender Antivirus along with Avast.