When trying to install OS X Yosemite on my MacBook, my Mac gives me the message "This partition map modification would make a Windows partition unbootable" with a Restart button beneath it, and when I click that button, my Mac restarts and this thing continues to loop.
Any ideas?
MacBook, OS X Mavericks (10.9)
I decided to format the whole disk (which had Mavericks, Windows 8.1 and Ubuntu 14.04 on it) and continue the installation. Now the installation goes fine, but I wouldn't say this is the solution to this problem.
The Yosemite installer may convert your disk to Core Storage and offer you the option to use File Vault (this option can be unchecked during the installation). However, Core Storage only permits two partitions, so you will have to sort this before trying Yosemite.
I also believe that Bootcamp must be setup using the Bootcamp Assistant and after installing the primary operating system. So be sure to have your Windows and Ubuntu saved to external disks, before going any further. (Also external backup of your Mavericks too, for that matter)
Is there a solution that doesn't involve formatting the whole disk? I get the same error message and the installer won't continue. Then I restart and the installer loads again, same error message, etc. So basically I'm stuck in a loop and the Mac has become unusable.
I'm sorry that I couldn't help you with this problem 😟
To exit the loop do not click restart. In the top left corner click on OSX installer and select quit. It will then give you the option to select a your start up disk, select it then it will restart your mackbook to how it was before unharmed
I actually had the same problem, due to the fact that I have three partitions, osx, windows and an exfat to be a shared home partition for both OSX and Windows.
I found a solution to the problem:
Use Carbon Copy Cloner to copy my OSX drive onto a usb external drive which had no extra partitions.
Use System Preferences/Startup Disk to boot the usb drive.
Run the OSX upgrade on the usb drive install instead.
Use Carbon Copy Cloner to copy the usb drive back to the osx drive.
It worked perfectly without having to change/risk my other two partitions!
This partition map modification would make a Windows partition unbootable
