# Partitioning/Formatting external hard drive



## mgmcc (May 25, 2006)

I am trying, without success, to partition & format an external hard drive so that the first 40GB can have a bootable backup copy of my MacMini's hard drive (using "SuperDuper") which means using "Mac OS Extended (Journaled)" as the file system and "Apple Partition Map" instead of Master Boot Record as the Partition Scheme.

However, I want to be able to use the remaining 120GB of the drive with Windows PCs. As soon as I partition with Disk Utility in the Mac, the drive is unreadable in Windows. 

Basically, how can I get Mac and Windows partitions to co-exist in the same external drive, which is "Firewire" to be bootable with the Mac?


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## Ben123 (Dec 28, 2006)

I am guessing you are using bootcamp. Bootcamp will make it's own partition when you install it.


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## sinclair_tm (Mar 11, 2005)

i hope he's not using bootcamp. i hope you are using apple's disk utility. and you are half way there. after formating the first part for the mac, you can then select the second partition that you want for windows, and tell the mac to format it for windows (it may be called format for msdos - it should then do it as fat32). then when its done, you should be able to plug it into a windows pc and it should mount. windows will not see the mac partition, but the mac will see both.


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## mgmcc (May 25, 2006)

No, I'm not using Bootcamp, I'm using Apple's Disk Utility but don't appear to have the option to format the second partition as "MS-DOS File System" unless I set the Partition Scheme to Master Boot Record. For the Backup in the first partition to be bootable, I have to set the Partition Scheme to "Apple Partition Map" which removes the option of "MS-DOS File System" for the second partition.


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## sinclair_tm (Mar 11, 2005)

well, if that is the case, then it doesn't work like i thought it did. which for you means that you will not be able to do what you like.


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## ArturoYee (Nov 10, 2006)

Try formating two partitions first on the Windows. Give it names so it is easy to determine the partitions.
Then let the Mac format the second partition as HFS Plus.
_(its been some time since I've done this, if above does not work, try formatting the first partition HFS Plus...)_

But the key is that the Mac, as Sinclair noted, is more robust in reading the partitions. Windows needs to create the partition(s) to read it.


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## MChiriboga (Sep 6, 2008)

Perhaps it has something to do with the following

In Options you'll see several choices, the first "GUID Partition Table" is for Intel-based Macs. The second choice "Apple Partition Map" is for PowerPC-based Macs. Select the choice that is appropriate for the Mac you are on, then click OK. You should now be able to format the drive as Mac Os Extended with Journaling on or off. 

I'm about to embark on the same endevour you are detailing. I haven't tried yet, but have been researching prior to the attempt to get some background and avoid pitfalls. Maybe the above information I found will help, but I'm not convinced. I also wonder if we can make a bootable partition if we first Partition with a Windows based system. I am kind of skeptical about that. I hope to find some more info. Please share if you have had further experience. Thanks, Mark


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## sinclair_tm (Mar 11, 2005)

Oh boy, this is an oldie. Alright, it works this way, you can not make a drive that can boot both Macs, and Windows using any Windows app, or Apple's Disk Utility. Only one OS can boot from it, and the one you want to boot from it has to be the one to format the disk. As stated, the format writes a table to the very beginning of the disk where the hardware looks for an OS pointer. If you just need a disk that can mount on both OSes, then format it FAT32.


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## MChiriboga (Sep 6, 2008)

Thanks Sinclair. Yes, I thought that was the case. I don't need to boot in both anyway. I went ahead and partioned and formated Mac OS extended for my Clone boot drive (I used SuperDuper free-share ware to make the ghost copy and it works great). I networked my old G4 up and copied everything over to the fire wire drive that way. She be enough back up for me and hopefully I'll be able to work with some of the old files at least. Thanks for the response.


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