My MBP's HDD is half OSX and the other half is Bootcamp (Windows 8.1 - no upgrade; a clean install using W8.1-compatible BC drivers).
While booted into Mavericks I decided to let Software Update upgrade to Yosemite. I left the room. Upon returning a while later I found the following error message: "a mismatch between the MBR and GPT partition maps is not supported".
Because the system currently wants to repeatedly try the installation (and fail) is it possible to stop this process and boot back into Mavericks? It looks like there's a dmg mounted by the upgrade. I'm hoping this partition problem was detected early in the upgrade process, before my existing installation was changed -- but I haven't a clue how Apple does OS upgrades, if rollbacks are possible, etc.
Second question: I've read forum posts about this exact problem and they all refer to running "Terminal" and using GDISK to edit the partition tables. The instructions look easy and vaguely familiar, but I have no idea how to interrupt this upgrade process, run Terminal, install GDISK, etc. I can follow instructions and probably did this sort of thing a couple decades ago or more in the DOS and early Windows world, but I know very little about the Linux and Apple environment.
Answers appreciated!
While booted into Mavericks I decided to let Software Update upgrade to Yosemite. I left the room. Upon returning a while later I found the following error message: "a mismatch between the MBR and GPT partition maps is not supported".
Because the system currently wants to repeatedly try the installation (and fail) is it possible to stop this process and boot back into Mavericks? It looks like there's a dmg mounted by the upgrade. I'm hoping this partition problem was detected early in the upgrade process, before my existing installation was changed -- but I haven't a clue how Apple does OS upgrades, if rollbacks are possible, etc.
Second question: I've read forum posts about this exact problem and they all refer to running "Terminal" and using GDISK to edit the partition tables. The instructions look easy and vaguely familiar, but I have no idea how to interrupt this upgrade process, run Terminal, install GDISK, etc. I can follow instructions and probably did this sort of thing a couple decades ago or more in the DOS and early Windows world, but I know very little about the Linux and Apple environment.
Answers appreciated!