Bootcamp not booting any more after OSX partition resize

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Level 1

18 points

Bootcamp not booting any more after OSX partition resize

Hi community,

I am having a problem that I am sure many of you already would know how to solve. I read several posts about the subject but all of them have a different approach and I am not sure which one to follow.

I guess that when I reduced the size of the OSX partition to make more space for the Bootcamp partition the Windows partition stopped booting because the partition table changed its order with the new free partition auto created by OSX?

I come from the Windows world and if you resize a partition then you would have "Unpartitioned Space" not another partition created automatically that in this case seemed to have messed things up.

I have no experience with partitions in OSX, maybe somebody can give me hand please how can I fix this to merge the free 2 50 GB partitions into the Bootcamp partition and fix the boot option too?

Also if I can better understand if in the future I need to resize again partitions how do I prevent things from breaking again? Maybe there is an OSX App to do this in an easier way?

As you can see in the below images, I have gathered information which I read might be useful to identify the partitions to fix the problem.

I have expanded the OSX partition 2 times thats why there are 2 empty partitions of 50 GB, I would like to add these 100 GB to the Bootcamp partition.

Thank you very much for your help to fix this issue.

MacBook Pro with Retina display, OS X El Capitan (10.11.3), Late 2013 model full specs.

Posted on Mar 29, 2016 12:08 PM

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Answer 1

Loner T

Level 9

59,471 points

Mar 29, 2016 5:29 PM in response to Surferride

1. What is the version of Windows?

2. Was Windows working properly before the resizing of OS X?

3. On Macs, resizing Bootcamp is generally not supported - Boot Camp: Resize the Windows partition . Your model may support it, if installed using EFI Boot, but that is not an option now.

4. Please post the output of

diskutil list

5. You may temporarily lose Recovery HD, if you want to preserve your Windows installation.

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Answer 2

Surferride Author

Level 1

18 points

Mar 30, 2016 1:26 PM in response to Loner T

Hi, please find below the details of the partitions with Disk util.

Its a Windows 10 installation and yes it was working perfectly before resizing.

So basically I would need to delete the Bootcamp partition and then merge it with the other 2 partitions of 50 GB each and then reinstall Windows?

I have read several people with the same problem and they didn't seem to have to reinstall at all...sounds a little bit odd...

Thanks for your support

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Answer 3

Loner T

Level 9

59,471 points

Mar 30, 2016 3:08 PM in response to Surferride

Let us try this first. Please backup all your data, or as much as possible. You should still be able to see Bootcamp volume in OSX Finder. If not, we can create a temporary Hybrid MBR, if necessary.

1. Run mergePartitions as

diskutil mergePartitions jhfs+ "Macintosh HD" disk0s2 disk0s4

2. After merge completes, re-install OSX to get your Recovery HD back.

3. Once you have EFI, OSX, Recovery HD and Bootcamp in order, post the output of (the disk slice number is after the merge completes).

sudo dd if=/dev/rdisk0s4 count=1 2>/dev/null | hexdump -C

4. Was W10 an upgrade to an existing W7/W8? Do you know if your Windows installation is BIOS or UEFI?

Here is the help syntax for mergePartitions. Please note the highlighted parts.

diskutil mergePartitions

Usage: diskutil mergePartitions [force] format name

DiskIdentifier|DeviceNode DiskIdentifier|DeviceNode

Merge two or more pre-existing partitions into one. The first disk parameter

is the starting partition; the second disk parameter is the ending partition;

this given range of two or more partitions will be merged into one.

All partitions in the range, except for the first one, must be unmountable.

All data on merged partitions other than the first will be lost; data on the

first partition will be lost as well if the "force" argument is given.

If "force" is not given, and the first partition has a resizable file system

(e.g. JHFS+), it will be grown in a data-preserving manner, even if a different

file system is specified (in fact, your file system and volume name parameters

are both ignored in this case). If "force" is not given, and the first

partition is not resizable, you will be prompted if you want to erase.

If "force" is given, the first partition is always formatted. You should

do this if you wish to reformat to a new file system type.

Merged partitions are required to be ordered sequentially on disk.

See diskutil list for the actual on-disk ordering; BSD slice identifiers

may in certain circumstances not always be in numerical order but the

top-to-bottom order given by diskutil list is always the on-disk order.

Ownership of the affected disk is required.

Example: diskutil mergePartitions JHFS+ NewName disk3s4 disk3s7

This example will merge all partitions *BETWEEN* disk3s4 and disk3s7,

preserving data on disk3s4 but destroying data on disk3s5, disk3s6,

disk3s7 and any invisible free space partitions between those disks;

disk3s4 will be grown to cover the full space if possible.

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Answer 4

Surferride Author

Level 1

18 points

Mar 31, 2016 12:41 PM in response to Loner T

Hi, thanks for your comments.

I didn't lost the Recovery partition. I would like to avoid reinstalling completely my computer.

Arent there any ways to fix this in some simple steps without reinstalling?

Thanks for your support

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Answer 5

Loner T

Level 9

59,471 points

Mar 31, 2016 1:09 PM in response to Surferride

Since Recovery HD is between OSX the two partitions, which we want to merge, temporarily, you will lose Recovery HD, but you are not reinstalling from scratch. If you were planning to add the two Untitled partitions to Bootcamp partition, then we can convert the 90+GB parts to Free Space and you will need to

1. Use Gparted to extend the BC partition, and,

2. Recreate the MBR using GPT Fdisk and run Startup Repair.

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