Altering Disk Partition size on rMBP OS El Capitan

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Level 1

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Altering Disk Partition size on rMBP OS El Capitan

Hi there,

I have a rMBP with latest OS and I have a 500GB SSD. Currently I have 350GB on my Mac and 150GB on bootcamp. I've been thinking about changing this to 400GB Mac and 100GB BC but avoided doing this because I heard that I would have to erase/reformat drive etc.

I noticed however that there is a Disk Utility program on the Mac and there was an option to increase the size and the way it's worded, suggests that I select the size I want and press APPLY. This seems way too easy!

I've attached an image of the screen.

Is it just a question of altering the size and applying it or am I being too optimistic?

Thanks

MacBook Pro with Retina display, OS X El Capitan (10.11.1), null

Posted on Dec 2, 2015 5:53 AM

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Answer 1

Top-ranking reply

keg55

Level 6

11,743 points

Dec 2, 2015 7:19 AM in response to Maz K

Is it just a question of altering the size and applying it or am I being too optimistic?

You're being too optimistic. 🙂

Unfortunately, to resize the Bootcamp partition, you have to use Bootcamp Assistant, remove that partition and recreate it for the size you want. Also, you don't want to add another partition (split your OS X partition) while you have a Bootcamp partition. The partition map somehow gets messed up and you may not be able to boot back into Bootcamp.

To do what you want to do (400 OS X partition, 100 Bootcamp partition) you need to:

Run Bootcamp Assistant and remove your current Bootcamp partition. This will put that free space back into your OS X partition.
Run Bootcamp Assistant again and size that partition to 100GB and reinstall Windows. This will recreate your Bootcamp partition size and install Windows.

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Answer 2

Maz K Author

Level 1

54 points

Dec 2, 2015 7:28 AM in response to keg55

Hi keg55,

Thanks for your reply. Not what I wanted to hear - I use BootCamp to run Windows specific software so I might do what you've suggested after getting my serial numbers from the company for the software I use or I might transfer my iTunes data to BC which is 50Gb or so in size - just the right amount of space I am wanting to add.

Don't feel confident enough to re-partition, it may be a straightforward thing, but if it does cause me problems, it'll be pretty difficult for me to solve I think.

But thanks for your help.

Maz

Forgot to ask, if I run BC assistant, am I right in thinking that the Windows I have is genuine as I bought my computer used. I hadn't really thought about genuine windows but not sure now. Does running BC automatically allow for Windows 7 to run?

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Answer 3

keg55

Level 6

11,743 points

Dec 2, 2015 7:37 AM in response to Maz K

You're welcome.

Is the extra 50GB that you have in your Bootcamp partition really going to be a problem? I only ask because as you use that more and more and add data and/or apps, you may just need that extra 50GB. So, if you recreate it minus that 50, and then in the future need it you would have to do what I suggested to increase the size.

I know I had too large of a Bootcamp partition but I kept it because I had enough space on my OS X partition not to worry about it filling up.

EDIT: To answer your question of "Forgot to ask, if I run BC assistant, am I right in thinking that the Windows I have is genuine as I bought my computer used. I hadn't really thought about genuine windows but not sure now. Does running BC automatically allow for Windows 7 to run?"

When you install Windows 7 or 8.1 or 10, you will have to provide the product key as if you were installing it fresh on a PC. Bootcamp Assistant will create your Bootcamp partition, download and add the Bootcamp drivers for Windows 7, 8.1 or 10 to your Windows install thumb drive and finally install Windows. Don't know if this helps.

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Answer 4

keg55

Level 6

11,743 points

Dec 2, 2015 12:48 PM in response to keg55

Sorry.. not sure I answered your "Does running BC automatically allow for Windows 7 to run". If you're referring to setting your Startup Disk to your Bootcamp partition, the answer is yes. My wife's MBP Retina is setup that way. Anytime she restarts or shutdowns then starts, Windows 7 runs since Bootcamp is the Startup Disk.

The Bootcamp drivers has a Windows system tray icon to manage your Bootcamp Preferences. So if you want, you can change your Startup Disk there if you want to startup in OS X or mess with your mouse and keyboard settings and a few other things.

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Answer 5

Maz K Author

Level 1

54 points

Dec 2, 2015 12:51 PM in response to keg55

Hi again,

Thanks for the extra info. I think, like you say, the extra 50GB isn't going to be a a pressing need. I wrongly thought that I could easily adjust the partition size and apply changes judging from the screen image I showed. As it's not the case, I will probably stick to leaving things as they are.

Mac OS is authorised to read/write on BC (BC isn't authorised to write to files on the Mac partition) so I will transfer my iTunes data to BC and then can access it easily. It may even be the case that in the future, I would want that extra BC space anyway.

So I'll leave things as they are.

Many thanks for your advice.

Maz

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