How to fix "libobjc.A.dylib is being read from process memory" error

If your app takes forever to run on a device and you get the following error in the console log, I can share a solution that solves the problem for me.

warning: libobjc.A.dylib is being read from process memory. This indicates that LLDB could not find the on-disk shared cache for this device. This will likely reduce debugging performance.

Cause of the problem

LLDB, a debugger in Xcode, will copy and cache a necessary binary from a device to make a debugging process faster.

Xcode copies them to ~/Library/Developer/Xcode/iOS\ DeviceSupport.

If the process fails, then LLDB has to fallback to reading information from the device, which causes slowness each time you run an app.

I don't know what caused the copy process to fail since it might have come from many reasons.

• I suspected it might come from the Xcode beta I downloaded.
• It might cause by the fact that I manually remove things in the Developer folder to get back my spaces and cause some files to be corrupt.

For whatever reason, the cache was corrupted, and Xcode couldn't retrieve the necessary information.

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How to fix "libobjc.A.dylib is being read from process memory" error

To fix this problem, we need to clean up a corrupted file inside ~/Library/Developer/Xcode/iOS\ DeviceSupport.

Here are the steps:

1. Close Xcode,
2. Use the following command to remove the cache.

rm -r ~/Library/Developer/Xcode/iOS\ DeviceSupport

3. Reopen Xcode and rerun the app. Xcode would find no cache this time because we just deleted them. It will copy the binaries again, which fixes the problem in my case.