I'm not sure what triggers it (possibly a restart?), but every once and a while I notice that the drop shadows under explorer windows go away. I then go to Advanced system settings > Performance settings > turn on Show shadows under windows. This turns the shadows back on until they get turned off again at some point. I never see it happen, so I'm not sure what triggers it. Any ideas how to get this setting to stick?
There are so many possibilities that might cause your issue that might take long to troubleshoot.
First of all It's important to know if your issue have occured after an update, after an installation of a software, driver etc.. If so, it could be a bit easier to troubleshoot.
Otherwise, I'd suggest the following:
Check GPU driver
CMD -> Chkdsk /f // Find any windows corrupted files and repair, while I suspect this step is useless but is worth trying
Check any active software that might interfere with your desktop like desktop recording videos if you have, try closing them.
Restarting explorer.exe does change anything? (cmd command: taskkill /im explorer.exe & explorer.exe)
For now that's all comes in my mind to try it, It can even be a registry issue or antivirus one (very rare).
So just leave the shadows turned off. Simple.
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