Windows won't boot when OS X drive is plugged in...

I've been running Windows 7 through bootcamp happily for the last several months. Everything more or less worked as it should until recently during some hardware upgrades (new processors). For some unknown reason, the boot sector on my OS X drive got corrupted and I had to reinstall 10.10. I had a Time Machine backup from that morning so all was well. Until I used Startup Disk to try and jump over to my Windows drive (Windows is installed on a separate drive, not a separate partition on the same drive as OS X). The computer reboots, gongs, then goes to a black screen and I never see the blinking cursor or anything. It just hangs on a black screen. I tried rebooting and holding option and selecting the Windows drive, same thing. If I unplug my OS X drive (an OWC PCIe SSD) Windows loads up and works fine. I'm mildly technical, but I don't know where to begin here. The Mbr is fine because windows will boot up sans OS X drive, Disk Util sees the Windows drive, Startup Manager sees the Windows drive. They just can't seem to get it to boot. Any help you lot can lend will be greatly appreciated.

2009 Mac Pro

3.46 Ghz Westmere

32GB RAM

GTX 780

OS X 10.10 on OWC PCIe SSD

Windows 7 on Samsung 840 Pro running through CalDigit FASTA-6GU3 Pro (for SATA 3 speed)

I know thats a bunch of mod-ish stuff, but like I said, Windows and Boot Camp were all playing nice earlier this week. Also I already zipped the PRAM.

Mac Pro, OS X Yosemite (10.10.2)

Posted on Feb 15, 2015 4:57 PM

17 replies

Feb 20, 2015 8:41 AM in response to Loner T

Sorry for my late response. Turns out you were right, sort of. I had my OWC PCIe drive plugged, and my Windows drive plugged in to one of the original SATA connectors. I pulled the CalDigit card and rebooted. Everything worked. I could switch between both OSes as usual and all was well. I plugged the card back in, while leaving the Windows drive plugged into the OEM connectors, all was well. Everything still worked as it should. Lastly, I plugged the Windows drive into the CalDigit card and we were back in business. So the CalDigit card just need to be "reset" as it were. Thanks so much for your help man, you went above and beyond for a stranger on the internet.

Loner T

Level 9

59,536 points

Feb 20, 2015 9:33 AM in response to Daniel miller

Glad to see it finally work. Thanks for allowing me to learn about the CalDigit FASTA card in the process. Noted for future reference.

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Windows won't boot when OS X drive is plugged in...