Hi,

I don't have the Mac version of QuickNII in front of me, but somewhere inside there's a file called pack.txt (most probably it's at the exact same location where you found ABA_Mouse_CCFv3_2017_25um.cutlas), it contains the name of the cutlas file QuickNII will attempt to load. It contains the filename only, not even a line break after it.

I hope this helps, best regards,

Gergely