Windows ACM is a bandaid: intended for apps that are not fully color managed.  Qimage has full color management and lets you set your monitor profile to anything you like (even something different than what is identified in Windows).

In addition, Qimage is fully compatible with ACM because since Qimage is doing the color management, all image data that is sent to your display is sent tagged as "display ready".  As such, Windows ACM should not be touching the data and there should be zero difference seen on your monitor whether you turn on/off ACM because Qimage has control and most importantly, it is telling Windows not to use ACM because the data is already profiled by Qimage.  If you are seeing something that disagrees with that, you have something else going on.  We have tested Windows ACM and have a lot of people who use it and I've never seen it cause a problem in Qimage.  Are you sure you don't have some other software (perhaps a utility) installed that overrides the intended Windows behavior, perhaps to "force" apps to try to use ACM even when they shouldn't?  I ask because ACM will not work with most apps: an app has to specifically "make itself" compatible with ACM.  You can't just enable ACM and have it properly color manage an old app that knows nothing about color management: those apps won't know enough to tag the image data so that ACM can use it.

Regards,
Mike