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TheDeviceUser

macrumors 6502a
Original poster
Jul 20, 2014
589
72
U.K
I'm just about to partition my MacBook Air (Mid-2013) to create a 30GB drive for Yosemite. However, if I create a partition, is this permanent, because I want to be able to merge them back together into one drive once Yosemite launches this autumn.

Thanks
 
Nov 28, 2010
22,670
31
located
Partitioning is not permanent, but as you create a second partition after the first partition, any merging will mean the deletion of the second partition, as one can only change the end of a partition but never the beginning.

In other words, once you want to go OS X 10.10 Yosemite full throttle, you have to either install it on your first partition running OS X 10.9 Mavericks or clone the second partition to the first and then delete the second partition and resize the first partition to its original size.

Was that understandable with all the first and second and partition?
 

klamzi

macrumors member
Jun 13, 2014
33
0
You can remove later the partition.
Once you want to do that boot in recovery mode remove it and expand back your main partition to full size.:)
 

TheDeviceUser

macrumors 6502a
Original poster
Jul 20, 2014
589
72
U.K
Thanks to everyone who replied, yes I understand now! I plan to install Yosemite on the partition and keep Mavericks on my main drive but then do the upgrade to my main drive of Yosemite from mavericks when it's released and also delete the partition.

Thank you.
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,463
16,160
California
Thanks to everyone who replied, yes I understand now! I plan to install Yosemite on the partition and keep Mavericks on my main drive but then do the upgrade to my main drive of Yosemite from mavericks when it's released and also delete the partition.

Thank you.

A Yosemite install on a second partition will turn that partition into a core storage volume that can't be deleted by Disk Utility. You will need to follow this process to kill the Yosemite partition, then you will be able to use Disk Util to expand the remaining partition normally.
 

Traverse

macrumors 604
Mar 11, 2013
7,710
4,489
Here
A Yosemite install on a second partition will turn that partition into a core storage volume that can't be deleted by Disk Utility. You will need to follow this process to kill the Yosemite partition, then you will be able to use Disk Util to expand the remaining partition normally.

Would a simple restore from Recovery or Mavericks USB allow one to clear both partitions and do a clean install?
 

Weaselboy

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Staff member
Jan 23, 2005
34,463
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California
Would a simple restore from Recovery or Mavericks USB allow one to clear both partitions and do a clean install?

I don't believe it would because a recovery just puts the data back on the partition you point it to... and that would not fix this second partition issue. It needs to be resolved before the restore.
 

Dave245

macrumors G3
Sep 15, 2013
9,843
8,075
Before i download, i just want to check that having a Time Machine backup will be enough if anything goes wrong with Yosemite? i have backed up my MBP using Time Machine.
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,463
16,160
California
Before i download, i just want to check that having a Time Machine backup will be enough if anything goes wrong with Yosemite? i have backed up my MBP using Time Machine.

The answer is a qualified yes. It will depend on how much free space you have on the TM backup disk. As the disk gets full TM will purge off data. So if your external disk is getting close to full and it has been a while since you switched to Yosemite, it is possible parts of the data you need to restore could have been purged. But if you have lots of space, you will be okay.

You can just option key boot to the TM disk the use Disk Util to erase the entire disk, then click restore and pick a restore date from prior to the Yosemite install.
 

Dave245

macrumors G3
Sep 15, 2013
9,843
8,075
The answer is a qualified yes. It will depend on how much free space you have on the TM backup disk. As the disk gets full TM will purge off data. So if your external disk is getting close to full and it has been a while since you switched to Yosemite, it is possible parts of the data you need to restore could have been purged. But if you have lots of space, you will be okay.

You can just option key boot to the TM disk the use Disk Util to erase the entire disk, then click restore and pick a restore date from prior to the Yosemite install.

Thank you, and yes i think i have around 205GB left on my external hard drive that I use for Time Machine.
 

Jumpie

macrumors 68020
Jul 7, 2008
2,129
1,765
Atlanta
A Yosemite install on a second partition will turn that partition into a core storage volume that can't be deleted by Disk Utility. You will need to follow this process to kill the Yosemite partition, then you will be able to use Disk Util to expand the remaining partition normally.

I'm not sure what I did but here's the gist.

I opened Diskutil and saw that I could not delete the Yosemite partition. So I was following some steps I was reading in these forums.

In Yosemite, I ran diskutil cs list and it returned an output but I don't remember what it was. Then I ran Diskutil from Yosemite and saw I still could not remove the partition because it was the startup.

I then went into Mavericks, ran diskutil cs list and it returned an output. I don't remember what. I opened Diskutil and saw that I can now delete the Yosemite partition. But, is this safe to do? I'm assuming yet because I can't delete the Mavericks since it's now the startup.

For shiggles, I went back to Yosemite and opened Diskutil and saw I could not delete its partition because it's the startup but could delete the Mavericks one.

So back to Mavericks I go. I will keep the partitions for a while to test it out. Actually, i do kind of like it. But I also wish that Photos and some other things were included, too.
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,463
16,160
California
I then went into Mavericks, ran diskutil cs list and it returned an output. I don't remember what. I opened Diskutil and saw that I can now delete the Yosemite partition. But, is this safe to do?

Assuming you no longer want Yosemite on there... totally safe.

(Upvote for "shiggles". :D I'm stealing this.)
 

chrisrand

macrumors member
Aug 17, 2013
74
2
Easy fix

I'm just about to partition my MacBook Air (Mid-2013) to create a 30GB drive for Yosemite. However, if I create a partition, is this permanent, because I want to be able to merge them back together into one drive once Yosemite launches this autumn.

Thanks

I know this is an old article, but this recently happened to me and the easiest way to get rid of the Yosemite partition is to:

1) Boot your other OS, mine was Mavericks
2) Open Disk Utility
3) Select the Yosemite partition
4) Select the erase tab, erase it,
5) Select the main drive and go to the partition tab, where you can then delete the Yosemite partition and resize it back to the original size.

Hope that helps!
 
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