I'm having that exact same issue but it happens less often. I'm also using Windows 10 64-bit to run MAME as well (having Win 10 installed on my SSD and an additional hard drive). This issue happens even though MAME is on my SSD.
It doesn't just happen with MAME too, certain applications do this as well (present in Demul) after the OS either runs for an extended period of time or something triggers it to run in some "low power" state. It's not understood what is going on but I predict it's something on Windows 10. Regardless, it's impossible to get the OS running back to normal without restarting your computer.
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