I prefer unmerged sets, so I can delete any romset I want without care of if it's the parent of another nor anything else...

I'll try to explain what I got:

My steelta1.zip contains the following files (31 files):

Searching ZIP: /roms/steelta1.zip

Length Method Size Ratio Date Time CRC-32 Attr Name
------ ------ ----- ----- ---- ---- -------- ---- ----
65536 DeflatX 41931 37% 10-26-2003 11:17 562066d0 --w- a003210s.087
65536 DeflatX 33262 50% 10-26-2003 11:17 392c992d --w- a004200s.087
65536 DeflatX 29773 55% 10-26-2003 11:17 5c1437e9 --w- a005210t.087
65536 DeflatX 23158 65% 10-26-2003 11:17 a99873fc --w- a006200t.087
65536 DeflatX 21708 67% 10-26-2003 11:17 f343ae79 --w- a007210u.087
65536 DeflatX 17918 73% 10-26-2003 11:17 8a118c41 --w- a008200u.087
65536 DeflatN 21794 67% 10-05-2002 02:19 420be93b --wa 1007210u.087
65536 DeflatN 17936 73% 10-05-2002 02:19 78e72af9 --wa 1008200u.087
65536 DeflatN 35287 47% 10-05-2002 02:19 53e9fe94 --wa 1009210v.087
65536 DeflatN 35097 47% 10-05-2002 02:19 7eff9f8b --wa 1010200v.087
65536 DeflatN 42630 35% 10-05-2002 02:19 b388bf91 --wa 1011210w.087
65536 DeflatN 42566 36% 10-05-2002 02:19 d39e8cef --wa 1012200w.087
65536 DeflatN 44919 32% 10-05-2002 02:19 f6b99901 --wa 1013210x.087
65536 DeflatN 45028 32% 10-05-2002 02:19 9f047de7 --wa 1014200x.087
65536 DeflatN 42501 36% 10-05-2002 02:19 ef517db7 --wa 1015210y.087
65536 DeflatN 42493 36% 10-05-2002 02:19 db62362e --wa 1016200y.087
131072 DeflatN 36024 73% 10-05-2002 02:19 0a29db30 --wa 1017-2lm.087
131072 DeflatN 9464 93% 10-05-2002 02:19 a5882384 --wa 1018-2t.087
65536 DeflatN 4365 94% 10-05-2002 02:19 4c645933 --wa 1025-5f.087
65536 DeflatN 11777 83% 10-05-2002 02:19 c52d8218 --wa 5001-1f.087
131072 DeflatN 32589 76% 10-05-2002 02:19 c904db9c --wa 5002-1m.087
131072 DeflatN 40923 69% 10-05-2002 02:19 164580b3 --wa 5003-1n.087
131072 DeflatN 93125 29% 10-05-2002 02:19 296290a0 --wa 5004-1p.087
131072 DeflatN 110821 16% 10-05-2002 02:19 c029d037 --wa 5005-1r.087
8192 DeflatN 2378 71% 10-26-2003 11:17 2956984f --wa 9007-10c.087
65536 DeflatN 24706 63% 10-05-2002 02:19 b4fa2900 --wa 1001210r.087
65536 DeflatN 18727 72% 10-05-2002 02:19 31bf01a9 --wa 1002200r.087
65536 DeflatN 42225 36% 10-05-2002 02:19 7802e86d --wa 1003210s.087
65536 DeflatN 33316 50% 10-05-2002 02:19 c31ca924 --wa 1004200s.087
65536 DeflatN 30078 55% 10-05-2002 02:19 1107499c --wa 1005210t.087
65536 DeflatN 23379 65% 10-05-2002 02:19 01ebc0c3 --wa 1006200t.087
------ ------ --- -------
2367488 1051898 56% 31

But steelta1 only need thoose (25 files):

This is the list of the ROMs required for driver "steelta1".
Name Size Checksum
1002200r.087 65536 CRC(31bf01a9) SHA1(cd08a839dbb5283a6e2bb35bc9e1578a14e3c2e6)
1001210r.087 65536 CRC(b4fa2900) SHA1(5e92ab4af31321b891c072305f8b8ef30a3e1fb0)
a004200s.087 65536 CRC(392c992d) SHA1(10d1606214df675e6e59185e6b97034c4a47055a)
a003210s.087 65536 CRC(562066d0) SHA1(69973dbdb1580942e8d22eee4ee130ecd67885fd)
a006200t.087 65536 CRC(a99873fc) SHA1(5f4c0c2ca38d800ec8b2d4d6adf74901249bd794)
a005210t.087 65536 CRC(5c1437e9) SHA1(c0dd4db5ecbbeb90b64fdaeb5abfcbe06fbd09cd)
a008200u.087 65536 CRC(8a118c41) SHA1(4312cd09b2ce3ad181f07c564962640b2431b913)
a007210u.087 65536 CRC(f343ae79) SHA1(63cf2e76de9ca12d916cafed7d7030965756b0b6)
1010200v.087 65536 CRC(7eff9f8b) SHA1(7e6ee7dec75bc9224834d35c0b9a7c5d8bd897bc)
1009210v.087 65536 CRC(53e9fe94) SHA1(bf05ce2f8d97e7be96c99814d280289ffad1621a)
1012200w.087 65536 CRC(d39e8cef) SHA1(ba6aa8b70c30d6db70cfcf51dfe450dcfde0f3e4)
1011210w.087 65536 CRC(b388bf91) SHA1(3e6a17e4462023f59f6581b09c716e6c51e7ae8e)
1014200x.087 65536 CRC(9f047de7) SHA1(58c4f062d8eef9e2d0143a9b77b066fc3bb5dc29)
1013210x.087 65536 CRC(f6b99901) SHA1(5c162a6d945c312e49e0a1e04285c597dde4ef94)
1016200y.087 65536 CRC(db62362e) SHA1(e1d392aa00ac36296728257fa26c6aa68a4ebe5f)
1015210y.087 65536 CRC(ef517db7) SHA1(16e7e351326391480bf36c58d6b34ef4128b6627)
5001-1f.087 65536 CRC(c52d8218) SHA1(3511c8c65583c7e44242f4cc48d7cc46fc748868)
9007-10c.087 8192 CRC(2956984f) SHA1(63c9a99b00c3cbb63aca908b076c2c4d3f70f386)
1025-5f.087 65536 CRC(4c645933) SHA1(7a1cf049e368059a79b03598de73c30d8dae5e90)
1018-2t.087 131072 CRC(a5882384) SHA1(157707b5b114fa584893dec07dc456d4a5520f44)
1017-2lm.087 131072 CRC(0a29db30) SHA1(f11ad7fe27989ffd66e9bef2c14ec040a4125d8a)
5002-1m.087 131072 CRC(c904db9c) SHA1(d25fff3da87d2b716cd65fb7dd157c3f1f5e5909)
5003-1n.087 131072 CRC(164580b3) SHA1(03118c8323d8a49a65addc61c1402d152d42d7f9)
5004-1p.087 131072 CRC(296290a0) SHA1(8a3441a5618233f561531fe456e1f5ed22183421)
5005-1r.087 131072 CRC(c029d037) SHA1(0ae736c0ca3a1974911464328dd5a6b41a939130)

So, there are 6 unneeded files that ClrMamePro is not deleting...
If I delete those files manually the set works fine (without it's parent on the ROMs folder), but I have the same problem with lot of other romsets (lot of work to do it manually).

Is something I am doing wrong? It's ClrMamePro fault?

Roman: Thanks a lot for your support.

> When using unmerged roms each set needs each rom...which is a big waste of
> diskspace. But with this scan mode no romfile is unneeded, no file will be
> listed and/or removed. It is VERY uncommon to use not/un-merged files. Are you
> sure you want that?
>
> If a file is marked as unneeded it will be removed correctly.
>
> Roman Scherzer
> ClrMamePro
>