On some macs Capture One would crash immediately upon launch after the user updated to OSX 10.7.4 (read more on our Capture One blog).This was due to an unexpected change by Apple in the way Open CL (communication with the graphics card) is handled.Capture One 6.4.2 has just been released to address this issue.
Order of install doesn't matter. Just so long as you aren't trying to run <6.4.2 in 10.7.4.