Unity 5.6.0f3 crashing on splash screen fix12 May 2017
I lost a few hours trying to get unity to run, only to crash at the splash screen and get greeted by the bug tracker!
Anyway for me it was down to some little bloatware called LavasoftTcpService64.dll. It’s hard to find but best way to rule this problem out is to install AdwCleaner. This found the problem (amongst others I am too ashamed to admit).
Anyway if you still have problems, here is an official doc of other possible causes, good luck!