Snes9x.com

snes9x 1.53 (using 64-bit) is overwriting some extensions already associated by 7zip like .gz, and some extensions don't make sense to associate with snes9x like *.a for compiled static libraries.

I'd rather snes9x, or any other program, not mess with file type associations unless I explicitly tell it to...

Edit the Valid.Ext file in the snes9x directory.

S9x will never overwrite extensions, it merely adds itself to the "open with" list for filetypes listed in valid.ext. I've removed most of the legacy extensions in 1.53, and even more in further testbuilds. You might still have an old valid.ext from older versions that contains .a and so on.