Having the same problem. Unity 2017.2.0f2 and originally with 7.10.1, but I have tried updating to 7.13.0 with same result.
In the facebook settings window, it says:
“Your android debug keystore file is missing. You can create new one by creating and building empty Android project in Eclipse.”
I have done a lot of different things to be absolutely sure that I have the debug.keystore. It even said that the password was wrong of file had been tampered with at some point. So it can find it, but the error message might be wrong?
For my case (window), base on Peter77’s suggest ( link ), there is a “‘keytool’ is not recognized as an internal or external command” error in my debug.log. So i added the java keytool to my PATH and restart window. Problem gone
If you integrating FacebookSDK you need to go to Edit → Preferences → External Tools → unclick Android SDK checkbox → click browse button → press select folder → Android Dependencies will be downloaded → click Android SDK checkbox ->Ready!
I ran into the same issue and the solution for me was to install openssl (on Windows) and add it to the PATH environment variable. Make sure you also have some Java SDK correctly installed too. Both keytool and openssl should be available in the command window under any path if correctly done.