Invalid active developer path on MAC OS X after installing Ruby

Question

I get this error:

xcrun: error: invalid active developer path (/Applications/Xcode.app), missing xcrun at: /Applications/Xcode.app/usr/bin/xcrun

Answer 1

[Update] The steps below are for OS X 10.10 (Yosemite). Those experiencing this because of an upgrade to 10.11 (El Capitan) seem need to only run sudo xcode-select --install as described in the accepted answer.

I found a suggestion here which indicated

sudo xcode-select -switch /

as the fix. However, this threw an error that the developer path was invalid.

Instead, for me, I modified this to

sudo xcode-select -switch /Applications/Xcode.app/Contents/Developer/

(which is a mixture of the two referenced link solutions) and this worked.

[Edit]

Try using

xcode-select --print-path

to find your developer path if /Applications/Xcode.app/Contents/Developer/ is still invalid for you.