Loading a plug-in failed.
The plug-in or one of its prerequisite plug-ins may be missing or damaged and may need to be reinstalled.
I tried deleting Xcode and doing a fresh install but got the same result. I then noticed that when I ran Android Studio it said it could not locate Git, so I tried to run git from the Terminal and got an error, so I ran xcode-select --install and the subsequent update downloaded but failed to install.
xcodebuild: error: Initialization failed.
Reason: Loading a plug-in failed.
git: error: sh -c '/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -find git 2> /dev/null' failed with exit code 17920: (null) (errno=No such file or directory)
xcode-select: Failed to locate 'git', requesting installation of command line developer tools.