I have a late-2013 MacBook Pro running the latest Mac OS Sierra (updated this afternoon). I have Windows 10 installed on a Boot Camp partition.

I decided to decrease the size of the Mac OS partition as I'm running low on space in the Boot Camp partition. So I used Disk Utility to shrink the Mac OS partition, then formatted the unused space as FAT32.

There were no reported problems.

I then restarted the MacBook. It's set to boot directly into Windows, but when I restarted all I got was a blank screen. I waited... but got nothing.

So I forced the MacBook off (holding the power button) and restarted again, this time holding : I got to the partition selection screen, from where I clicked on "Windows". It froze. The pointer becomes unresponsive. Again, nothing.

I can still start up and select to boot into Mac OS but I can do nothing with the partition from where I do my job, leaving me in a bit of a panic.

In Disk Utility, I've clicked on the top-level disk, "Apple SSD", and selected "Repair", and after ~2 seconds it said something like "OK". I don't have an option to click on "Repair" when I click on any of the partitions.

I haven't used any third-party software, using only Disk Utility for its own purpose, and haven't touched the Windows partition.

Please, can someone tell me how to get my Windows partition booting once again.

I've since removed the empty partition which I had cerated, merging it back into the Macintosh HD partition.

Here is the output from running diskutil list:

/dev/disk0 (internal, physical):  
   #:     TYPE NAME                       SIZE       IDENTIFIER
   0:     GUID_partition_scheme           *500.3 GB  disk0  
   1:     EFI EFI                         209.7 MB   disk0s1  
   2:     Apple_CoreStorage Macintosh HD  249.4 GB   disk0s2  
   3:     Apple_Boot Recovery HD          650.0 MB   disk0s3                                            
   4:     Microsoft Basic Data BOOTCAMP   249.6 GB   disk0s4  
   5:     Windows Recovery                471.9 MB   disk0s5  

/dev/disk1 (internal, virtual):  
   #:     TYPE NAME                       SIZE       IDENTIFIER  
   0:     Apple_HFS Macintosh HD          +249.0 GB  disk1  
          Logical Volume on disk0s2  
  • Golden Rule - don't ever touch Boot Camp other than with Boot Camp Assistant. There are a couple of guys on here [...in the world!...] who have the skill to fix this. I hope they pick up your case. Wish you luck.
    – Tetsujin
    Jul 30 '17 at 18:29
  • Please tell us you had a full backup before you started ....
    – Solar Mike
    Jul 30 '17 at 20:17
  • Yes, I have backups of both OSs. But I'm a freelancer/contractor and this hiccup means I can't work. It'll take at least a full day to get everything back to where I was so I'm desperately hoping someone can tell me how to set that partition as bootable once again.
    – awj
    Jul 30 '17 at 20:21
  • That at least is a good position to be in with the backups - hope you get a solution
    – Solar Mike
    Jul 30 '17 at 20:36

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