I noted Eric Wings post on: "Command line instruments broken with pre-iOS 6 devices".
I'm running XCode 4.5 and I too am experiencing similar problems:
3GS with iOS 6 -- works
3GS with iOS 5.1.1 - unable to start: Instruments Trace Error: Failed to start trace.
iPad2, iPhone4S with iOS 5.1.1 - works
iPhone 4 with iOS 4.3.3 - unable to start: Instruments Trace Error: Failed to start trace.
Note that this is invocation via commandline (instruments script).
When invoked through XCode UI (UIAutomation tool) it works on all configurations - so it seems this is a commandline issue only.
Did anyone manage to get closer to a solution (other than managing several installations on different machines/virtuals)?
xcode4.5 iPad2 + iOS5.1.1 does not work for me
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