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28

Did you happen to use Apple's Disk Utility to create a FAT filesystem in that to-be-Windows partition? If so, you converted the disk from a legal GPT disk into a hybrid MBR disk, which OS X sees as GPT and Windows sees as MBR. The solution in this case is to clear the hybrid MBR data. A number of utilities can do this. I'll describe how to do it with my own ...


22

OK, it was a very involving process, but I solved my problem and everything works together just as it should. I'm documenting the solution for everyone: One must begin with GParted Live and create a fresh GPT partition table. This will wipe everything on the HDD resp. SSD. Then one must create a small 8 MB 'unpartitioned' partition and flag it with ...


22

First, you're conflating two or three different things (perhaps because of poorly worded program messages): Firmware type -- Old PCs used the Basic Input/Output System (BIOS), but new computers use the Extensible Firmware Interface (EFI) or its newer variant, the Unified EFI (UEFI). The main duty of both the BIOS and the EFI is to start the boot process, ...


17

Since you mentioned GParted, try this: Launch GParted on the disk. If any partitions are mounted (as indicated by a lock or key icon), unmount them. Select Device->Create Partition Table. Click Apply. The disk should now use MBR. You can also create partitions within GParted, if you like; however, the Windows installer can do this automatically if you ...


13

Intel-based Macs use the GUID Partition Table (GPT) by default. GPT in turn supports up to 128 partitions by default (that value can be increased if necessary, although most partition tools don't enable you to do so). Thus, there's no problem with having more than four partitions on an Intel-based Mac. The limitation you've heard about is a distortion of ...


12

Differences between MS-DOS style Master Boot Record (MBR), the Apple Partition Map (APM), and the UEFI-style GUID Partition Table (GPT) are such: Disk size MBR and APM limit the usable disk size to 2 TiB (a partition can neither start nor end beyond the 2 TiB limit). With GPT, the disk can be up to 8 ZiB. Partition count MBR is limited to four ...


12

If you have a Windows 7 Installation disk, you can enter Repair mode and use diskpart to accomplish this. From Windows 7 DVD, click Repair your computer when you see this screen: Then select Command Prompt in the Repair window: Once you've entered the command prompt, type diskpart to enter the utility. Type select disk # replacing "#" with the ...


9

This sounds like your Win7 was installed with EFI-support enabled but your Win8.1 installation is booted using CSM (Compatibility Support Module), which fakes a BIOS and Win8.1 subsequently thinks it's bootet on a BIOS system, which requires installation on an MBR-style disk. Try deactivating the CSM in your EFI settings (something like Boot Mode: UEFI ...


8

First point: To support more than 2.2 GB, the disk must be formatted as GPT, not as MBR. Second point: Even if the disk is formatted as MBR, you should be getting 2.2 TB, not 746 GB. The fact that this is not happening could point to a problem with the firmware. You should first check for BIOS and USB controller firmware updates,as well as update for the ...


8

Chances are the disk used to be a GUID Partition Table (GPT) disk. Such disks have partitioning data from sectors 0-33 (typically) and also in the last 33 sectors of the disk. If a GPT disk is repartitioned by a GPT-unaware utility, that utility is likely to replace just sector 0 (the MBR), leaving most of the GPT data intact. Technically, the disk is then ...


8

Microsoft erroneously conflates has an EFI partitioned hard disc with has EFI firmware. This is, of course, clearly wrong. It's quite possible — and indeed is becoming ever more desirable these days — to have an EFI partitioned disc on a machine that has old non-EFI firmware. Moreover, as of revision 2.3.1 of the UEFI Specification, the EFI ...


7

Typical USB drive enclosures have historically only supported up to 1.5 TB of capacity. I have a feeling this has something to do with the 32bit nature of the enclosure, but I could be totally off on that one. Make sure the enclosure's specifications state that it supports drives larger than 1.5 or 2 TB. Thus far, I have only seen USB 3 (SuperSpeed) ...


7

Assuming you mean Disk Utility, you have to select the drive itself (as opposed to an individual partition)*, and then you will see a Partition tab. Then on that tab, select the partition layout you want, and at the bottom click 'Options...' — you'll be able to select GUID Partition Table from there. ( * Apologies if this is patronising, but just to be 100% ...


7

You could use Paragon GPT Loader ($19.95) which : Allows the use of all disk space on a 2.2TB+ drive under Windows XP Augments Windows XP by adding support for GPT disks Or you could use the free GIGABYTE 3TB+ Unlock Utility to create two virtual drives on the disk : 2TB + 1TB, if your motherboard is on the supported list.


6

Well, things have changed since I first asked this question. For one, my PC is now UEFI based, so I don't have this problem anymore. Well, sort of. I had interest on pulling a similar setup on my laptop (GPT partitions, etc.) I finally managed to get a working Tianocore UEFI DUET setup, and it was about as painfully simple as it gets! This assumes you want ...


6

None of the answers so far gave me all the info I needed to solve this problem. I solved it and I'm successfully running my old Windows MBR install on UEFI and GPT now. Connect only your target drive and run Windows 7 Setup in UEFI mode. You can do this by enabling UEFI in the BIOS and by using the DVD. It is possible to make a USB stick that UEFI boots, ...


6

I eventually found the solution by using gdisk (gdisk - Interactive GUID partition table (GPT) manipulator). This what I did: Run sudo gdisk /dev/sdc Option s to sort the partitions Review changes by using option p And finally write the changes to the disk with option w


6

I only know of three partition schemes: MBR, GPT, and APM. (These are the ones Apple's Disk Utility can create.) MBR (Master Boot Record) is used historically by Windows (and, therefore, by most computer manufacturers). I'm not certain if you can boot a Mac from an MBR disk; I don't think so. GPT (GUID Partition Table) is generally used in conjunction with ...


6

There's no need to regress to the MBR partitioning scheme, nor even any need for a "hybrid MBR" partitioning scheme. (I have such on one of my machines, and attest that they are not for the fainthearted.) Windows 7 can use EFI-partitioned discs just fine. It just cannot be bootstrapped from them on non-EFI machines, and (to protect you from yourself, in ...


6

The statements about "Long LBA" seem to originate from that one Seagate product manager. What she probably meant is that even though 48-bit LBA is the standard on hardware, 32-bit OSes and drivers may not support all 48 bits, since (a) they're 32-bit and that's more hassle, and (b) MBR only supports 32 bits for partitions anyway, so why bother. When the ...


6

"There is nothing magical about 3TB drives.". True, but there is as soon as you hook it up to a USB bridge chip which is the magic that facilitates connectivity. A USB-attached device "speaks" the SCSI command set. This requires a protocol and command conversion. The problem is that since SCSI was first implemented decades ago, the most common commands, ...


6

Yes, second (non-bootable) harddrive can be formatted to GPT and recognized by Windows Server 2012 R2 regardless of firmware/motherboard support of GPT and UEFI. This applies to Windows 7 and Windows 8 as well. Please note: both disk C: and hidden system reserved partition with BCD hive must reside on MBR-formatted disk less than 2TB, because both of them ...


5

You need to understand the differences between BIOS-mode (aka CSM or legacy-mode) booting and EFI-mode (aka UEFI-mode) booting. Windows ties these boot modes quite closely to the partition table type: Windows will boot in BIOS mode if and only if the disk uses the older Master Boot Record (MBR) partition table type, and in EFI mode if and only if the disk ...


5

When your computer turns on, press the appropriate F# key on to enter your system's BIOS/EFI. In there look for a mode setting that allows you to choose between booting in CSM (Legacy), or EFI, choose EFI mode. Save your changes, exit the BIOS/EFI, and boot up the Windows installation disc. You should now be able to format the disk as GPT, and install to ...


5

Deleting the disk signature solved the problem. This can be done with the command dd if=/dev/zero of=/dev/sdb bs=1 count=4 seek=440 conv=notrunc in a linux shell with root rights. Background: Starting with Windows 2000, Microsoft writes a 4-byte value -the disk signature- into the MBR of each disk so that it can identify each disk. When two disks have ...


5

What would happen if I delete the EFI partition and reformat as MBR partition table on an external drive not booted from? Nothing. It would still just work. But you do seem to mix EFI and GPT, so let me give a longer answer: MBR is a very old way of partitioning drives on a PC. It only allowed for four primary partitions, or, with a workaround, for ...


5

It looks like something has trashed your GPT data -- both the main data structures and the backup data structures. I don't know specifically what might have done this, but a buggy partitioning tool seems like the most likely culprit. Another possibility is that there's been some confusion over something like a RAID configuration -- if the disk was originally ...


5

Recent computers use EFI, not BIOS, although manufacturers are confusing the issue by using the term "BIOS" in reference to their EFIs. The EFI boot process doesn't involve loading boot code from the disk's first sector, as it does with BIOS. Thus, disks aren't really bootable under EFI in the same sense that disks are bootable under BIOS. Instead, the EFI ...


5

It looks like the problem was the partition table. $ diskutil list /dev/disk0 # The internal hard disk #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.1 GB disk0 1: EFI 209.7 MB disk0s1 2: ...


5

Windows Vista and 7, and presumably 8, only support installing to a GPT disk when the installer is booted using UEFI rather than BIOS emulation. This is a configuration setting in your "BIOS" (really a misnomer on a UEFI system). Consult your motherboard's manual to find out how to boot from the install media without using BIOS emulation. (And make sure ...



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