After updating my iPhone 5 to ios 12.1, I get this error in xcode:
Could not locate device support files. This iPhone 5s (Model A1457, A1518, A1528, A1530) is running iOS 12.1 (16B92), which may not be supported by this version of Xcode.
What can I do about this?
Quicker/Smaller Fix
If you don't want a big Xcode update due to limited storage/time then you can manually download the required support files instead of the whole update.
I was on Xcode 9.4 so I downloaded the files from here and pasted in /Applications/Xcode/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport
Give a try with https://github.com/NikKovIos/XcodeDeviceSupportFiles/tree/master/12.1%20(16B91)
Check the readme of the repo to find how to install it.
Download latest supported device support file and add it manually in
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport
https://github.com/xushuduo/Xcode-iOS-Developer-Disk-Image/releases
Enjoy
