Hi Demagul, sorry for the late reply. I think it's not exactly the same thing between our OS versions, anyway the steps I did, mistake included are:
1) Start PSLauncher;
2) When asked to update say yes;
3) The launcher starts its update routine;
4) When finished to download the pslaunchmacosx.zip it crashes;
5) Then I go to the installation folder (mine is Applications/PlaneShift);
6) Extract by double clicking the pslaunchmacosx.zip: a folder is created (I can't remember the name... probably it was named Planshift) containing pslaunch.app and art and data folders;
7) Here is the mistake I did: those 2 folders (art and data exctracted in the previous step) just contain the files needed only by the launcher, not the whole planeshift installation. So I overwrited the new pslaunch.app and the data and art folders to the original ones by dragging the extracted files out of the folder created during the pslaunchmacosx.zip unzipping;
Now if you try to execute the pslauncher it will stall;
9) Kill the process;
10) Open the old PlaneShift-v0.6.0.dmg; (yes I did it because I kept it from a previous download)
11) Select the art and data folders contained in the PlaneShift-v0.6.0.dmg and drag them into your planeshift installation directory so you have all the files (even if outdated) needed to run the launcher again. As you can see I don't overwrite the updated pslaunch.app with the previous contained into the dmg file;
12) Start again the launcher: it will say it needs to be updated;
13) Start updating again: here everything should go fine until the end of the update;
14) To be sure, after the process ends, quit the launcher;
15) Start again the launcher (now it's updated so it shouldn't ask you to update) and do a repair;
16) If everything has gone fine as in my case, the launcher should inform you that all files passed the MD5 checksum;
I hope this guide can help you to get in game as soon as possible!