Q: I can't boot to Windows after resizing my Mac partition.
So, I recently decided to resize my bootcamp Win7 partition. This is something I have done successfully before, by:
1) Booting into Macintosh
2) Using Disk Utility to decrease the size of the Mac partition (20GB the first time)
3) Booting into Windows
4) Using Mini-Tool Partition Wizard (third-party) to allocate the free space to the Bootcamp partition.
There were a couple issues caused by this the first time around, mainly the fact that Macintosh didn’t recognize the fact that the free space had been taken, and had trouble reading from the Windows partition. However, I could live with that. I have since rebooted to both Mac and Windows several times without problem.
Recently, I decided I needed a bit more space, and so started to follow the above steps, shrinking the Mac partition an additional 15GB. Only when I went to reboot to reallocate the space, the Windows partition didn’t show up as a bootable option. Confused, I booted back to Mac, and the Bootcamp partition was still there, but renamed “disk0s4”, and unmounted. Reparing the disk failed (“Invalid BS_jmpBoot in boot block: 15921e”). The disk wouldn’t mount (not even sure if it was supposed to be mounted earlier, but that’s what it looks like). It also appears grayed-out in the list of drives to the left. It looks like I can create a dmg from the windows drive, although I haven’t done that yet (I will soon).
Any solutions for this? Although I will erase the drive if absolutely necessary, it would be preferred if that wasn’t the first option to try. I had no problems like this the first time I resized the disk.
(My mac partition is running Mavericks, if that is of any relevance)
MacBook, OS X Mavericks (10.9), Mid-2010 MC516
Posted on Aug 6, 2014 6:04 AM
Boot Camp 5.1: Frequently asked questions
How can a Windows partition be resized after Windows is installed?
You need to delete the Windows partition using the Boot Camp Assistant, and start over to change the size of the Windows partition. Back up your important Windows files first.
Please post the output of
1. diskutil list
2. sudo fdisk /dev/<BootcampDisk> (of the form disk0 as shown by 1.)
3. sudo gpt -vv -r show /dev/<BootcampDisk> (of the form disk0 as shown by 1.)
4. sudo dd if=/dev/<BootcampDiskSlice> count=1 2>/dev/null | hexdump -C (of the form disk0s4 as shown by 1.)
Posted on Aug 6, 2014 8:41 AM



