Hello below I have cut and pasted from another apple discussion and what I am pasting worked for me, I also have multiple user accounts on the mac and would get the same dmg error on all other accounts except admin. followed this to a 'T' and it worked a treat. this was with latest version non legacy 1.8.9 i think it was . When I nut out how to link this to that discussion I'll edit this post
" Reply Helpfulby djcmvpeyton on Oct 25, 2015 11:46 AM
The fix I found was to look at the permissions of the Application. /Applications/Minecraft.app I noticed that they were Owner: R+W,Admin: RO, Everyone: RO. I initially changed this at the app level by doing a "Get Info" and changing them to all being R+W. This did not fix it. I then navigated to the app file and right-clicked and selected "Show Package Contents". Then selected the "Contents" Folder and right-clicked and selecting "Get Info". At this info page I unlocked(bottom right corner) and changed both admin and everyone to R+W. then I selected the gear (bottom middle) and selected "Apply to enclosed Items...". At the prompt click "OK". then the app opens in the other accounts.
App Level --> change R+W for all
Contents Level --> Change R+W for all and then apply to enclosed items "
Just realised this is for El capitan this above solution worked for yosemete. I can't see why this solution wouldn't work for El Capitan. As we speak the mac in question is downloading El Capitan, I reckon my fix will carry through. I will drop back hear and let you folks know if I had any issues. 🙂
