Until very recently, instruments worked fine. I don't know what I did to make it mad, but now it won't attach to any device that I try to Profile with; no device at all. I've tried an iPhone, iPad, and 2 iPod touches; no luck! I'm using XCode 4.
Here is the sequence of events:
- With device attached, click Product->Profile.
- App compiles onto device.
- Instruments launches, but an error sound is heard
- The record button is grayed out.
- Choose Target doesn't allow me to attach or choose target (empty list).
Background points:
- Profile is set to Debug build within the Scheme of the project. This is true for all static libs as well.
- I AM able to run the Core Animation instrumentation on the device, but only when I launch I launch Instruments separately from Xcode. In this scenario, i can only attach to an existing executable; I can't use "Choose Target" (the list is empty).
- I tried restoring one of the devices to factory settings...still didn't work.
Looking at the Console of the device, i see these messages:
unknown lockdownd[17] <Error>: 001d5000 handle_connection: Could not receive USB message #16 from Instruments. Killing connection unknown com.apple.mobile.lockdown[17] <Notice>: Could not receive size of message
Any help would be most appreciated
There was a discussion on the apple developer forums about this issue:
Instruments does not work on Xcode 4 with device
It appears that different Apple products will change/update the MobileDevice framework. Some of these updates break the Instruments integration.
To fix this on my own machine, I installed the iTunes 10.5 beta v6. Fire up XCode, and I'm back in business Instrumenting on my device.
May be worth a try - I had the same issue - I changed 'Targeted Device Family' from 'iphone/ipad' to 'iphone' in the build settings and this solved it for me.
I quit Xcode and Instruments, relaunched them, did a clean build, and then did Product->Profile, and Instruments magically started working again with my device. Go figure.
Have you also installed the latest developer builds of XCode 4.2 w/ the iOS 5.0 builds? I've found that even if you install it in a separate directory, it does something to the instruments in the original XCode 4 directory. Using the latest version of XCode will allow you to use it properly.
Workaround: Go back to Xcode and use Cmd-Tab to switch to Instruments. I have to do that twice to get Instruments running again.
来源：https://stackoverflow.com/questions/6297554/instruments-does-not-work-on-xcode-4-with-device