# Solved: Windows 7 ultimate x64 will not mount GUID partition table hard disk



## darthrevan945 (Jan 1, 1970)

hi all,
I have an external 3TB hard drive, USB. I used a mac to partition it, 2.25TB is HFS+ (Mac OS extended - journaled) and the other is 490gb NTFS (to use on windows). It would not give me the option to use MBR (master boot record) so i used the GUID table. It works fine on macs, but windows tells me i need to reformat it. It is my understanding that most all 64bit versions of windows can read/write a GUID disk. I do not need to boot off of the drive.

this is another addition to the list of "why i hate windows"

Thanks in advanced, any help is appreciated.


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## saikee (Jun 11, 2004)

I could be wrong but 64-bit Windows needs efi firmware to read a gpt hard disk.

My 64-bit Win7 see only the 2TB of my 3TB hard disk leaving the last 1TB dead unallocated hard disk space. The full 3TB is usable in Linux once I partition it with a gpt partition table.

Windows is light years behind Mac and Linux when it to utilisation of large capacity hard disks.


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## darthrevan945 (Jan 1, 1970)

I thought it only needed EFI to boot off of it. It's supposed to be able to read it other wise. I thought anyways. How do you suggest I go about doing this? I need an HFS partition for OS X to use it (NTFS write support for OS X is dead slow so i don't consider it), and NTFS for windows and linux to use it.


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## Lance1 (Aug 4, 2003)

Here's some interesting information for you to read; *Windows and GPT FAQ*

Also an interesting article here; *The woes of a GUID Partition Table* Older, 2007 but sheds some light.


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## darthrevan945 (Jan 1, 1970)

Thanks for your help, I was able to figure it out. the NTFS portion needed to be formatted within windows. Mac OS X apparently didnt format NTFS correctly so windows didnt like it.


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## saikee (Jun 11, 2004)

Sorry I can confirm that the 64-bit Win7 can see and mount gpt partitions formatted in NTFS.

I enclose the screen shot of my 3TB disk partitioned into 128 partitions. Win7 tried to mount all of them until running out of drive letter. I have i,j & k drives partitions formatted in NTFS and they show up in "My Computer". The i to z drives are from the 3TB disk.


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## darthrevan945 (Jan 1, 1970)

Thanks for confirming that. I did some research, it seems that all x64 windows OS's and x86 OS's post windows server 2003 SP1, should be able to mount GPT. This *excludes* windows xp 32bit.. windows xp 64, and server 2003 are Win NT 5.2, xp 32bit is 5.1 and does not support GPT. for future reference to anyone reading this forum.


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