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dastinger

macrumors 6502a
Original poster
Mar 18, 2012
818
3
Hey guys,

I have an external HDD that I use for backup purposes. It's a 1TB HDD but, at first, I only created a 256GB partition to work with Time Machine leaving 750GB~ of free space. Thing is, now I wanted to create another partition but Disk Utility won't let me. If I try to change the partition layout it just tells me it will format the HDD to create the partitions.

I know iPartition can do this but I don't want to spend $50 on an app to use one time.. is there any freeware or any way to do this under Disk Utility?

Thanks
 
Last edited:
Do you want to add a partition? Have you tried the + button instead of selecting a new partition scheme?
Yes, Time Machine started acting up after I formatted my MBP and I wanted to create a new partition to use with Time Machine without losing what I have backed up. At least for some time, while I'm not sure if I'll need it or not.

No, the +/- buttons are greyed out and I cannot click them.

macrumors_dikutility.png


Btw, is it normal that the 256GB SSD reads 251GB under Disk Utility?
 
Yes, Time Machine started acting up after I formatted my MBP and I wanted to create a new partition to use with Time Machine without losing what I have backed up. At least for some time, while I'm not sure if I'll need it or not.

No, the +/- buttons are greyed out and I cannot click them.

Btw, is it normal that the 256GB SSD reads 251GB under Disk Utility?

The reason you cannot resize that partition is because you formatted the existing partition as Master Boot Record (MBR), the old format for Power PC Macs. Click over to the Erase tab and reformat as GUID (under Options) and you should be able to resize and do whatever you want with the resulting partition.
 
The reason you cannot resize that partition is because you formatted the existing partition as Master Boot Record (MBR), the old format for Power PC Macs. Click over to the Erase tab and reformat as GUID (under Options) and you should be able to resize and do whatever you want with the resulting partition.
I thought about that when I formatted at first but I decided to go with it because, under Disk Utility, it says "Can also be used for devices that require DOS or Windows compatible file formats". Doesn't this mean that, if I want to format a partition as Mac Extended and other as FAT or NTFS, I need this partition type? Or will I be able to do that using GUID?

Thanks a lot!
 
The reason you cannot resize that partition is because you formatted the existing partition as Master Boot Record (MBR), the old format for Power PC Macs. Click over to the Erase tab and reformat as GUID (under Options) and you should be able to resize and do whatever you want with the resulting partition.

Just a small correction, if I remember correctly, MBR is for Windows formatted HDDs, older PowerPC Macs used the Apple Partition Map Scheme.
MR2ss_2013_04_09_pA1_DiskUtility_PartitionSchemes.png
 
I thought about that when I formatted at first but I decided to go with it because, under Disk Utility, it says "Can also be used for devices that require DOS or Windows compatible file formats". Doesn't this mean that, if I want to format a partition as Mac Extended and other as FAT or NTFS, I need this partition type? Or will I be able to do that using GUID?

Thanks a lot!

No, you can format the Mac partition(s) to GUID, then add other partitions like FAT or ExFAT with no problems. Where you get into problems is when you are trying to setup Windows boot partitions, and those need to be MBR, but it does not sound like you are trying to do that.

Just a small correction, if I remember correctly, MBR is for Windows formatted HDDs, older PowerPC Macs used the Apple Partition Map Scheme.

You are absolutely correct. Thanks for the catch.
 
No, you can format the Mac partition(s) to GUID, then add other partitions like FAT or ExFAT with no problems. Where you get into problems is when you are trying to setup Windows boot partitions, and those need to be MBR, but it does not sound like you are trying to do that.



You are absolutely correct. Thanks for the catch.
No, I don't want to boot into anything using this HDD in particular. All I want is the ability to have Mac Extended, FAT and/or NTFS partitions in the same HDD so I guess I'm good.

Thank you so much for your help, guys!
 
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