Question: When working I will have multiple windows of file explorer open at a time. If I than start working on something else and leave those windows open in the background, they will close themselves leaving only one of them open. I have tried going into task manager and restarting file exploiter and that didn't fix it. i am running Windows 10 pro. Does any one have any ideas on how to fix? 

Thank you!

Answer: 
The simple fix is to set the Drive Map GPO to use the Action UPDATE.

To stop your mapped drives disappearing or automatically closing:

Launch Group Policy Managementnetwork-mapped-drives-closing-spontaneously-automatically
Find your drive mapping GPO, right click on it and select EDIT
Expand USER CONFIGURATION > PREFERENCES > WINDOWS SETTINGS > DRIVE MAPS
Double click on the drive map that is automatically closing
Change the ACTION drop down from REPLACE to UPDATE
I had the same issue on a users machine, every time he opened file explorer it would just crash. He did get an Intel Optane error at first but after I uninstalled Intel Optane and rebooted that error went away, but the initial problem still persisted.

I eventually fixed it by setting explorer to open "This PC" instead of "Quick Access":

![enter image description here](https://i.stack.imgur.com/VljTE.jpg)