UltraARC for Inno Setup (Conversion Tool)

[KaktoR]

You have to write the mask groups in lowercase

$MscSolid => $mscsolid

Don't ask me why, but it works.

precomp is always used by xtool (well, the command precomp, not the tool). You can't call xtool without precomp command (precomp = precompression). That's what xtool is for. You can only change used codecs or options.

For uncompressable files use $void mask group (or your own). Open arc.groups with a text editor and add files to $void mask (by filename (+ subfolder) or by file extension (*.abc). You can define files for every other mask group or make a new group ($groupxyz).