> The selected game is missing one or more required ROM or CHD images
> And this is happening in the last MAME
> UMK 3 version 1.2
> What happened?
It works just fine, you just need to update your romset with the file(s) that MAME says are missing. In particular, from whatsnew.txt for MAME 0.181:
-Decapped and read out security pics for umk3 and rmpgwt. [CAPS0ff]
* Added a new device type and bare bones loading, however communication with the main CPU is not hooked up yet.
These are essential dumps for PCB owners to restore and fix their boards. But, since they are documented in MAME for everyone, they are required as part of the romset to load/operate the emulation.