User profile for user: clark6
clark6 Author
User level: Level 1
8 points

OK Same Topic New Thread Can't Install Windows In Boot Camp

Mid 2011 imac

12 GB Ram

2 TB Hard Drive - OMC replacement internal HD - Lots of disk space on both partitions.

OS Lion 10.7.5 - Clean install

Disk Utilites Version: 12.1.1 (353)

Boot Camp Version: 4.0.4 (437)


First

of all what type of formatting is normal for a Windows install? Is it

EFI or some other type of format? I have read that you don't want EFI

install because it causes problems. So what SHOULD it be?


Bootcamp after partitioning: 

Mac Hard Drive: Reads Journaled and GUID format

Boot Camp partition is MS-DOS (FAT) 


16 GB USB Flash Drive: Formatted in  Dos-32 (Fat)  before Boot Camp did install on it.


Created

USB Boot Camp installation for Windows 8.1 Pro. Downloaded support

files during installation to 2nd USB by checking only the install Boot

Camp files box. 


Went back into Boot Camp and Installed Windows in Boot Camp from ISO file by checking the other two boxes.


Disk Utilites INFO after USB creation:  Reads not bootable in Disk Utilities. 


USB

would not boot on restart. Option start lists the USB as EFI disk.

Click on that to install. Starts Windows install. Type in key. Window

goes to listed drives and reports error on all listed.


"Windows

can't be installed to this disk. The selected disk has an MBR partition

table. On EFI systems Windows can only be installed to GPT disks.


Windows can't be installed on this hard disk space. Windows must be installed to a partition formatted as NTFS."


Somewhere

the Boot Camp install has changed the hard drive from GUID format to

MBR in both the Mac partition and the Boot Camp partition when trying to

install Windows according to the error trying to install above. 


Rebooted into Mac HD.


Macintosh HD is now formatted in Mac OS Extended (Journaled) no mention of GUID format or MBR type.

Boot

Camp partition is still  formatted in MS-DOS (FAT). No mention in INFO

that it is formatted in MBR as it stated when trying to install windows

from EFI USB drive.


USB

Flash Drive Installer: Now the USB install flash drive reads Master Boot

Record in the top of Disk Utilites for the USB drive. So Boot Camp

erased and changed the USB flash drive from MS-DOS (FAT) to MBR

somehow. 


The USB 'Volume' WININSTALL is formatted still in MS-DOS (FAT).


​Tried

install again. Same errors. Where the drives are listed clicked on the

Boot Camp partition and clicked format. Same error. Booted into Mac.

Utilities info lists drive as NTFS which is supposeldly what windows can

be installed as. Rebooted again went into EFI Boot from Windows install

DVD disk is again in the MBR format. 


​So what gives?




Posted on Oct 20, 2025 8:25 AM

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User profile for user: Nathan Alden
Nathan Alden
User level: Level 3
984 points

Posted on Oct 22, 2025 5:25 PM

Here we go again. I'll go slower this time.


  1. With an erratic DVD drive, it will be tougher (but not impossible) to get Boot Camp going. You'll need to move up to High Sierra for the best possible outcome. So, head over to How to download and install macOS - Apple Support and get a new copy of macOS first. Many links are there, but I'm going to recommend Sierra toward the middle of the page. It's the latest "hard copy" available that will work. Some earlier stuff is up there, too, but El Capitan has a bugged certificate and was never fixed, so skip that one.
  2. Once you're up in Sierra, try the App Store link to High Sierra on the same page. If you are able to get it (it won't come up in many later OSes, so I'm unable to verify). Apply the upgrade ASAP.
  3. Use Boot Camp to go back to one partition. At this point, I'd like to see you start clean.
  4. You'll probably need a (spare) PC with Windows 10 or later to properly write a Windows image to USB. If you have one, then do the following:
    1. Get a 64-bit Windows 8.1 ISO image
    2. Download Rufus, a USB media writer.
    3. Plug the USB stick in that you want to use as a source.
    4. Run Rufus and select the ISO you downloaded. Hit START in the Rufus window to begin writing (this does take a hot minute, so be patient).
    5. Close Rufus. Remove your Windows stick and set it aside.
  5. Back on the iMac, run Boot Camp to get the drivers on a second USB stick and set up the volume for Windows as you like.. Do NOT restart yet -- we can't use a CD, but that's exactly where the iMac wants to go, so we need to get around that.
  6. Now, attach the Windows stick and .restart the iMac. Hold the Option key, and you should see four volumes. (mac, Recovery, Windows, and EFI). Choose Windows --this is the OS image you wrote.
  7. Quickly press a key to start Windows Setup.
  8. Assuming you're a bog-standard American, the language and keyboard options should be fine. Hit Next.
  9. Click "Install now".
  10. Agree to the license.
  11. Choose a "Custom install".
  12. CAUTION: This next screen should be where the partitions live. You MUST select the partition marked BOOTCAMP and click Format in the rows of buttons below to make this FAT partition an NTFS partition instead!!
  13. The installation should go on without any further input from you. Your computer might restart. If you're back in mac OS, restart your machine per Step 6; but this time, select the hard disk icon marked "Windows" to resume setup.
  14. You'll be in "first run" mode after a while. Answer the questions you see.
  15. Windows 8 will go to the Start screen. Click Desktop in the lower left.
  16. Unplug your Windows installer and set it aside.
  17. Plug in the Boot Camp stick
  18. Launch the File Explorer and locate the Boot Camp Setup file. Start it, and the screen goes darj. Click Yes to allow it.
  19. Follow all onscreen prompts, then restart.


--Nate


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1 reply
Question marked as Top-ranking reply
User profile for user: Nathan Alden
Nathan Alden
User level: Level 3
984 points

Oct 22, 2025 5:25 PM in response to clark6

Here we go again. I'll go slower this time.


  1. With an erratic DVD drive, it will be tougher (but not impossible) to get Boot Camp going. You'll need to move up to High Sierra for the best possible outcome. So, head over to How to download and install macOS - Apple Support and get a new copy of macOS first. Many links are there, but I'm going to recommend Sierra toward the middle of the page. It's the latest "hard copy" available that will work. Some earlier stuff is up there, too, but El Capitan has a bugged certificate and was never fixed, so skip that one.
  2. Once you're up in Sierra, try the App Store link to High Sierra on the same page. If you are able to get it (it won't come up in many later OSes, so I'm unable to verify). Apply the upgrade ASAP.
  3. Use Boot Camp to go back to one partition. At this point, I'd like to see you start clean.
  4. You'll probably need a (spare) PC with Windows 10 or later to properly write a Windows image to USB. If you have one, then do the following:
    1. Get a 64-bit Windows 8.1 ISO image
    2. Download Rufus, a USB media writer.
    3. Plug the USB stick in that you want to use as a source.
    4. Run Rufus and select the ISO you downloaded. Hit START in the Rufus window to begin writing (this does take a hot minute, so be patient).
    5. Close Rufus. Remove your Windows stick and set it aside.
  5. Back on the iMac, run Boot Camp to get the drivers on a second USB stick and set up the volume for Windows as you like.. Do NOT restart yet -- we can't use a CD, but that's exactly where the iMac wants to go, so we need to get around that.
  6. Now, attach the Windows stick and .restart the iMac. Hold the Option key, and you should see four volumes. (mac, Recovery, Windows, and EFI). Choose Windows --this is the OS image you wrote.
  7. Quickly press a key to start Windows Setup.
  8. Assuming you're a bog-standard American, the language and keyboard options should be fine. Hit Next.
  9. Click "Install now".
  10. Agree to the license.
  11. Choose a "Custom install".
  12. CAUTION: This next screen should be where the partitions live. You MUST select the partition marked BOOTCAMP and click Format in the rows of buttons below to make this FAT partition an NTFS partition instead!!
  13. The installation should go on without any further input from you. Your computer might restart. If you're back in mac OS, restart your machine per Step 6; but this time, select the hard disk icon marked "Windows" to resume setup.
  14. You'll be in "first run" mode after a while. Answer the questions you see.
  15. Windows 8 will go to the Start screen. Click Desktop in the lower left.
  16. Unplug your Windows installer and set it aside.
  17. Plug in the Boot Camp stick
  18. Launch the File Explorer and locate the Boot Camp Setup file. Start it, and the screen goes darj. Click Yes to allow it.
  19. Follow all onscreen prompts, then restart.


--Nate


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OK Same Topic New Thread Can't Install Windows In Boot Camp

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