I was also cleaning up an 0.174 set last night and the same kind of thing happened with that. The results pane was empty but the stats showed 3 missing sets and 58 missing ROMs. Unfortunately, I didn't save the cmpro.log from that but it was consistent with what the stats showed and after gathering the ROMs listed a subsequent scan showed 0 missing in the stats.
Just now I finished updating a set that was a few versions old to get it up to 0.225. This was done on a different computer from the other 2 with a new setup of clrmamepro. I'm getting the same deal. Missing 1 set and 37 ROMs in the stats but the scan results are empty. Screenshot and cmpro.log with duplicate entries filtered out are below.
cmpro.log contents:aristmk5\setchip v1.0.u11
aristmk5\setchip v1.0.u7
aristmk5\setchip v4.03.07.u11
aristmk5\setchip v4.03.07.u7
aristmk5\setchip v4.04.05.u11
aristmk5\setchip v4.04.05.u7
aristmk6\01040505.u70
aristmk6\01040505.u71
aristmk6\01040505.u83
aristmk6\01040505.u84
aristmk6\03130334_left.u70
aristmk6\03130334_right.u83
aristmk6\14011605_left.u70
aristmk6\14011605_right.u83
aristmk6\20012305_left.u70
aristmk6\20012305_right.u83
aristmk6\25012805_left.u70
aristmk6\25012805_right.u83
atarisy1\136032.105.l13
atarisy1\136032.107.b2
atarisy1\136032.115.j10
awbios\fpr-24363.ic48
bubsys\boot.bin
cdibios\zx405042p__cdi_slave_2.0__b43t__zzmk9213.mc68hc705c8a_withtestrom.7206
crysbios\mx27l1000-alt.u14
konendev\2v02s502_ifu.u190
megaplay\315-5349a.ic54
megaplay\315-5651.ic8
megaplay\315-5653.ic56
megaplay\315-5655.ic34
megaplay\315-5661.ic7
naomi2\epr-23607c.ic27
naomi2\epr-23609b.ic27
neogeo\uni-bios_4_0.rom
segasp\fpr-24329.ic72
stvbios\epr-17741a.ic8
tourvis\v4-54.ic29