How to merge partitions in El Capitan

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Level 1

6 points

How to merge partitions in El Capitan

Posted this is the iMac forum in error.

My 500gb hdd had 2 partitions until this morning when I decided to expand the partition with the OS on it to give the OS more room (Macintosh HD). So I reduced the size of the 2nd partition (Macintosh HD3) with the aim of merging the 'spare' into the OS partition. When I did this I had to create a new partition which I named Temp. But Disk Utility won't merge this with my OS partition. This seems to be something to do with the order they are listed - I think can make changes clockwise as it were, but the current sequence, L to R is HD3 - Temp - HD.

I've always been able to so this up to now but not in El Capitan it seems. Disk Utility seems to have been rewritten for people who like bright colours.

Neither of the other 2 partitions is essential - all backed up etc - if that's relevant.

I'm nervous about using terminal commands without expert guidance.

Thanks

iPhone 4S, iOS 6.1.3

Posted on Feb 15, 2016 2:53 AM

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Answer 1

keg55

Level 6

11,755 points

Feb 15, 2016 7:22 AM in response to Sago48

When you created your 3rd partition, it was split off the 2nd. So, all you can do is merge that 3rd back into your 2nd.

You would need to back up the data in your 2nd partition, delete both the 2nd and 3rd partition; then merge the free space back into your 1st. From there, you can recreate your 2nd partition and restore the data from your back up.

Do you know if your 1st partition is a CoreStorage (Logical Volume) partition? You can find out by opening Terminal and issuing the diskutil cs list command. If it comes back with no Logical Volumes Found or something like that then you don't have CoreStorage.

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Answer 2

keg55

Level 6

11,755 points

Feb 15, 2016 7:39 AM in response to keg55

Sorry, my prior post may not be helpful.

El Capitan's DU is really bad and very confusing. But you may have to do something similar to what I mentioned in my prior post. Select the slice that is your 3rd partition and delete it. If you're able merge its free space into partition 2 then you will need to select the partition 2 slice and delete it then merge the free space into partition 1. Then recreate your 2nd partition to the size you want it to be.

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Answer 3

Feb 15, 2016 8:00 AM in response to Sago48

Disk Utility: How to Resize a Mac Volume (OS X El Capitan or Later)

As you found out, there are certain rules about resizing partitions, one of which is indeed the order they are in. One of those rules is:

"To enlarge a volume, the volume or partition that is directly after the target volume must be deleted to make room for the enlarged target volume."

So depending on how your volumes are set up, you may be able to easily resize a volume, or you may need to copy volume data around a bit to get it in the correct sequence for resizing.

Tom

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Answer 4

Sago48 Author

Level 1

6 points

Feb 15, 2016 10:55 AM in response to Tom Nelson1

Thanks for the advice. It does seem that I will need to delete HD3 because it sits 'between' the OS partition HD and the free space I've created. I can do this easily, but I also wonder if there's a better programme that will enable me to deal with the hdd drive in the ways I want to.

I've been using EaseUS backup with success for a few years on my work pc and have just used their partition tool to resize the OS partition on my wife's pc, including shifting free space around the partitions, and it worked a treat. But as far as I can tell there's no version for OSX??

Thanks

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