I had a perfectly good triple-boot laptop running MacOS 10.6.8 (Snow Leopard, 32-bit), Windows 7 (32-bit), and Ubuntu (12.10? 32-bit, anyway). Apple's ads persuaded me that I should take the free upgrade to Yosemite. That started a nightmare.
First I had to do the download about 5 times (times 5 GB!!) because I kept getting "validation errors" on the download. Then the upgrade claimed that it could not install it on my hard drive because "the drive is locked". So I installed it on a USB stick instead. The install to the USB stick took over 10 hours. When I rebooted it later with the USB stick unplugged (thinking it would now boot Snow Leopard from my hard drive), it booted into the upgrade and eventually came up in OS X Yosemite. But at that point, it did not offer Windows or Ubuntu as boot options.
I figured it had wiped out (or lost contact with) rEFIt, so I refreshed it by installing rEFInd. After that, the rEFInd boot menu showed all three operating systems, but only OS X will boot.
After two days of research, I am beginning to think that the problem is that 32-bit and 64-bit OS-es cannot coexist on the platform.
Am I going to have to find a way back to Snow Leopard to get my triple-boot back? Or is there a magic stanza I can put in the rEFInd boot configuration file to make this work?