In software-lists the roms are recognized but all icons are blue. QMC2 knows their path and I ran Analyze roms tool (which showed the result: L:3252 C:0 M:0 I:0 N:0 U:3252). And I can run the games fine. It just can't show the state of roms (as in Correct, Mostly Correct, Incorrect, Not found etc.). For the arcade roms it works fine. This has been happening for the latest versions (I can't remember when it started happening though).
Never mind. It was the filter from the software-list toolbar that had the State filter disabled. I don't remember my self disabling it, but this is what caused it.
In software-lists the roms are recognized but all icons are blue. QMC2 knows their path and I ran Analyze roms tool (which showed the result: L:3252 C:0 M:0 I:0 N:0 U:3252). And I can run the games fine. It just can't show the state of roms (as in Correct, Mostly Correct, Incorrect, Not found etc.). For the arcade roms it works fine. This has been happening for the latest versions (I can't remember when it started happening though).