I've been trying to get Runex to run on my work laptop; MacBook Pro, late 2016, and I've had no success.  Additionally, I have encountered dozens of potential players that are unable to run the client on their Mac's. Hopefully, this will fix the login issues. The problem wasn't with the client itself, it's with OS X (obviously). When Yosemite migrated to El Capitan, it downloaded an older version of JDK (which is why other client sources are able to be executed but not Runex), furthermore, once El Capitan migrated to Sierra, it completely left out JDK 8 and only installed SE 6.  So, for the fix.  Delete all downloads of Runex Ensure SE is up to date System Preferences > Java (5th row on the bottom) > Update (you should be on 8 151) After updating your SE to 8 1311, install JDK 9 Updated JDK I'm not entirely sure why SE 6 was preloaded on such a new model, doing so caused OS X to be a bit temperamental and I was forced to remove it in-line. Loading and login issues should now be fixed. Download and run the client once again. * If you run into any updating errors, remove java from your device and reinstall it - Launchpad or Finder Search for terminal   Once you've successfully removed it, download Java again here After re-downloading Java, install the updated JDK provided in the link here Afterwards, download the client again and you should be good to go. Per @Logical - There is a problem a lot of Mac users have is with the 1 click function of their mouse while attempting to use an app such as RuneX that detects 2 mouse buttons.
Solution: This can easily be solved by going into your menu of devices, selecting your mouse and changing the setting from 1 mouse button to 2. ---------------------------------------------------------------------------------------------------------------------------------- AS OF DECEMBER 2019 - Seems after the winter update, there have been a lot of issues for Mac users attempting to update the client and having a return error of "client is outdated" or crashing. Some people have reported that the above solutions fixed their issues, while it did not for others. The next method below is what has had the most success since said update - Stay on u231.11 if you can, and then completely delete Runex. Open terminal, run - rm -R ~/.runex then rm -R ~/.runex-data Reinstall, re-run, and wait while it does it's thing.  ---------------------------------------------------------------------------------------------------------------------------------- 11/28/2017 edit - updated jdk location 11/29/2017 edit - changed version of java; 151 3/14/2018 edit - updated jdk location 4/24/2018 edit - mouse fix addition 2/14/2019 edit - fixed links, added new command lines to shorten the process 12/01/2019 edit - fixed links 12/24/2019 edit - added additional solution methods