Question: I have been trying to run the app to check the performance using `Core Animation` profiler in Xcode Instruments. Even though the device is online it shows up `Device is offline`. 

I tried getting the work done as per the various suggestions provided here [instruments-device-grayed-out](https://stackoverflow.com/questions/28913801/instruments-device-grayed-out). But nothing worked work apparently. 

Could anybody suggest how do i get this working. 

Specification:
**Xcode - 10.2
iOS - 12.2**

Here is the screenshot. 

[![enter image description here](https://i.stack.imgur.com/Z0yQO.png)](https://i.stack.imgur.com/Z0yQO.png)

Answer: 
The following worked for me (some steps may be unnecessary):

1. Quit Xcode
2. Unplug iPhone
3. Restart iPhone
4. Start Xcode
5. Plug in iPhone
6. Profile
In my case it turned out that my iPhone is not trusted my computer.

See my answer in this question:
<https://stackoverflow.com/a/60732605/3051096>