[adarnold]

I have the same problem. New Win8.1-64. On install of Calibre 2.1 all goes fine till it finishes and hangs (total freeze requiring power button) whole system trying to open Calibre. Installed as Admin and rebooted, still hangs when trying to start. Removed Calibre via win 8.1 (remove progs)and re-installed after a reboot. Still hangs after install.

Third time, unchecked "Start Calibre" after install. Tried running after reboot after install. Still no luck. I have been using Calibre on two Win7-64 laptops and my previous win 7-64 machine. This new one with Win8.1 seems to be a bit flakey anyway. BTW, I donated $35.00 a couple years ago on 1st install. Love the program and use it on the Win7-64 laptop till I can get W8 system using it. Thanks any and all for your time and it IS a wonderfull program. I have 2960 books and keep the library updated constantly.