SYSTEM: Running clean install of Win7 Pro 64-bit on a new Intel DQ77MK mobo with 32GB of installed and recognized 1333 DDR3 Corsair RAM. Boot drive is Samsung 840 Pro SSD, with additional WD Black SATA 6 HDD's for data, etc. Radeon HD 6670 (2GB) video card installed and drivers properly recognized by the OS. All mobo drivers successfully installed via the Intel factory supplied disc, and all USB 2.0 and 3.0 ports are recognized & functioning "properly". My BIOS ver. is "0054", but I have not updated to the latest "0058" simply because the release notes don't appear to address this PROBLEM in any way.
PROBLEM: IF I have an external drive plugged into any USB 3.0 port (front or rear panel) the system will hang at the opening Intel splash screen, on restarts or cold boots. Unplugging the external USB 3 drive allows the system to (re)start and boot into OS perfectly. I've already set boot priority to place internal C-drive as first boot device ... no fix. I've disabled "boot from USB" option in BIOS ... no fix. Further, it doesn't appear to matter what brand or size of external USB 3 drive is plugged into the system, as I experience the same problem with several different manufacturer's drives. I have seen MANY similar problems posted on the internet associated with different brands of mobo's and different brands of devices / controllers ... yet I have NOT seen any definitive FIX to the problem. The suggestion of disabling USB Legacy Support is unacceptable and would leave me with no USB KB or mouse at startup ... and this suggestion has yet to be proven effective. The suggestion to simply wait until after you boot the computer to plug in the external drive is also unacceptable. DOES ANYONE KNOW OF A REAL SOLUTION to this problem?
Any thoughts or constructive comments would be most appreciated. - Dan