I can't start Mathematica 10.2 in Windows 8.1 64 bit, I'm getting this error even after I uninstalled and re-installed.
I emailed support a couple fo days ago, but I'm yet to hear from them and I need to get to work ASAP, any ideas?
This error message has occurred before with a corrupted init.m file.
Check your init.m files if you have edited them. Otherwise, the article @JHM linked to you should fix the problem.