Freeze when I close the emu (0.9.9)

[[Unknown]]

Hmm. That would be in the NVIDIA driver.

Does this problem happen with both 32 and 64 bit versions of PPSSPP?

At the top, there's a dropdown that says Release, and next to it x64. If you change Release to Debug, and then do the same thing, you may get a much better stack trace. Unfortunately the current one only has NVIDIA driver stuff, and since they aren't kind enough to share details about their driver source code, it doesn't tell us much...

-[Unknown]