
More info, I tested it with image, copied png icons to ColorSchemes folder, with 1, 2, 5, no error, with 7 I had error, but I had to hold Ctrl+Q longer, some 20 seconds, then I removed first 2 copied png files, so the files 6 and 7 stay in the folder, and I had no error.
I think that loading of quick viewer is a bit slower with each png icon in ColorSchemes folder, so you could try to copy/paste all files in ColorSchemes folder 3 or 5 times, then it should be even slower - slow enough also for your PC.