When I launch Mathematica and write the first command and press
Return+Shift, whatever the command is, it takes forever to evaluate — about two minutes. Immediately after the first evaluation (even if I abort it) everything is back to normal.
If I then restart the kernel, the problem does not come back.
If I just wait for a couple of minutes after the start-up, the problem also does not appear.
From these observations, I would conclude that this problem is not related to the kernel (though I'm not a programmer).
I've been seeing this behavior since upgrading to 10.3 and it persists in 10.3.1.
Is this a bug? Is it Mac-only? Is it known?