Hey all.
When I try to add extensions to Chromium in a fresh installed Linux Mint Cinnamon 17.1 64-bit version, the screen turns black and I cannot recover the screen again, unless I turn my laptop off and restart??!!

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I have tried all the usual tricks there is to avoid restart, but can't figure anything new up.
What is the problem? How do I fix it? I will very much like to add extensions the the chromium.
Thanks in advance.
John