Re: Desktop screen keeps flashing after installing Windows 10 and can't open anything
I had the flashing screen problem (which is really a flashing desktop problem) yesterday after letting Windows install the first Windows 10 update. If the screen flashes, and then the icons flash, that's an indication that Windows Explorer, which runs the desktop, is crashing. This is often caused by an extension. Windows Explorer loads the extension, it crashes, Explorer crashes, and the cycle repeats once or twice a second. You can also start the Task Manager with Ctrl+Shift+Esc and you may see Windows Error Reporting using the CPU as it forwards reports to Microsoft.
The way to diagnose this is to use the Event Viewer. In the Task Manager (which is still usable when this happens), pick File->Run and enter "eventvwr.msc" without quotes. Click "Windows Logs", "System" and then click on one of the red stop signs (you may have to look at several).
That will usually give you the name of the offending DLL that Windows File Explorer is trying to load. Uninstall that application and the problem should be fixed.
In my case, it was actually a Microsoft DLL: cortana.dll that was crashing. I had turned off Cortana because it's not useful to me on a desktop system and I thought its data gathering was too intrusive. So I turned that back on, rebooted, and that solved the problem. I suspect I could turn it back off now, and just haven't gotten to that yet.
But there are any number of Windows File Explorer add-ins that could cause this problem, including iCloud.
I hope this helps someone. Wasted a bunch of time on this.