Unfortunately, this did not work for me. I'm running iMovie 11 v10.1 and even something as simple as starting and then immediately quitting will result in a SIGSEGV:
12/13/15 12:51:49.604 PM iMovie[9815]: WARNING: The Gestalt selector gestaltSystemVersion is returning 10.9.2 instead of 10.11.2. This is not a bug in Gestalt -- it is a documented limitation. Use NSProcessInfo's operatingSystemVersion property to get correct system version number.
Call location:
12/13/15 12:51:49.604 PM iMovie[9815]: 0 CarbonCore 0x00007fff93db3c9b ___Gestalt_SystemVersion_block_invoke + 113
12/13/15 12:51:49.604 PM iMovie[9815]: 1 libdispatch.dylib 0x00007fff9067f33f _dispatch_client_callout + 8
12/13/15 12:51:49.604 PM iMovie[9815]: 2 libdispatch.dylib 0x00007fff9067f237 dispatch_once_f + 67
12/13/15 12:51:49.604 PM iMovie[9815]: 3 CarbonCore 0x00007fff93d3fb47 _Gestalt_SystemVersion + 987
12/13/15 12:51:49.604 PM iMovie[9815]: 4 CarbonCore 0x00007fff93d3eddb Gestalt + 139
12/13/15 12:51:49.604 PM iMovie[9815]: 5 AVCHD 0x000000014e59254d _ZN13FDVDProcessor12FCDVDManagerC2Ev + 141
12/13/15 12:51:49.604 PM iMovie[9815]: 6 AVCHD 0x000000014e59eca7 _ZN13FDVDProcessor12FCDVDManager13GetDVDManagerEhhPFvvE + 87
12/13/15 12:51:51.724 PM iMovie[9815]: GVA warning: init, skip trailing zeros pps size = 5
12/13/15 12:51:51.724 PM iMovie[9815]: GVA warning: AVF_Get_Standalone_PPS, skip trailing zeros pps size = 5
12/13/15 12:51:52.996 PM iMovie[9815]: -[CIContext invalidate] not implemented
12/13/15 12:51:52.997 PM iMovie[9815]: -[CIContext invalidate] not implemented
12/13/15 12:51:53.171 PM sandboxd[140]: ([9815]) iMovie(9815) deny hid-control
12/13/15 12:52:17.607 PM AppleCameraAssistant[701]: SendPropertiesStateChangedMessage: Could not notify client iMovie on port 15455 - 0x10000003
12/13/15 12:52:17.614 PM com.apple.xpc.launchd[1]: (com.apple.iMovieApp.193632[9815]) Service exited due to signal: Segmentation fault: 11