Today I have updated xcode. when i tried to run project on simulator(ios version < 9.0) I got this error.
"Unable to open liblaunch_sim.dylib. Try reinstalling Xcode or the simulator runtime.
It ran perfectly on ios9.0 simulator.
here is screen shot. please help me.
This will also occur when you don't have the simulator actually installed within XCode. I recently upgraded to XCode 7.1 and didn't install all simulators and received this same error.
- Go to Preferences -> Downloads
- Verify you have a checkmark next to the desired Simulator you are trying to run within XCode.
- If no checkmark, then install the simulator of choice. 8.1, 8.2, 8.3, 8.4
I don't think that there is an "officially supported" way to solve this yet, but have a look at this answer (which originates from this more detailed troubleshoot) for a potential fix.
[Edit] In you case, try running those:
sudo cp "/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 8.1.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/host/liblaunch_sim.dylib"{,.bak}
sudo ln -sf "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/lib/system/host/liblaunch_sim.dylib" "/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 8.1.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/host/liblaunch_sim.dylib"
First, find the target file:
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/lib/system/host/liblaunch_sim.dylib You need make backup liblaunch_sim.dylib
Second, copied to destination (Remember to backup)
/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 7.1.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/host/liblaunch_sim.dylib And If need it to: iOS 8.1.simruntime iOS 8.2.simruntime iOS 8.3.simruntime All done.
Hope it helps.
I faced similar problem this problem occurs when we have multiple versions of Xcode Installed ... So i force quit all the xcode and simulator and then open the xcode version you want to open.
来源：https://stackoverflow.com/questions/32821827/unable-to-open-liblaunch-sim-dylib