I tried to install the new version of IntelliJ IDEA today and I got this strange problem.
Error! Can't initialize plug-ins directory. Please try again later!
Some searches on the Internet made me think that the problem was not from IDEA installer, but from Windows itself. I could later confirm that by fire up the installer of Format Factory and got the exact same error messages.
I took me an hour to try out different things until I got this forum thread: http://www.bleepingcomputer.com/forums/t/544157/error-cant-initialize-plug-ins-directory-please-try-again-later/.
Basically, the permission settings on the Temp folder of my user profile was messed up, and my account did not have any permission on that folder at that moment.
In short, the fixed is simply go to the Properties of that folder (you can type %temp% in Run to go to the folder directly), jump to Security tab, choose my user account, press Edit, and put a tick on Full control.
There were several error messages saying that I could not change the permission of some subfolder, but ignoring those folder does not causing me any problem till now.
I hope it help if you are having the same problem!