How to fix the xcrun error after an MacOS update

I’ve been running the beta of MacOS Sierra for a while now and, apart from the odd niggle (which I’ve obviously reported), all has been fine. That was until I went to use my Subversion client for the first time…

xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

Now, the issue here is that the command line tools are either missing or broken. The same happened after El Capitan, so this appears to be a general issue and one that, sadly, Apple don’t seem to fix.

The solution is simply to re-install the required software again. Open up a Terminal window and type the following…

xcode-select --install

It will take a short while to download and install but it should get you up and working again.