Disk formatting problems when on windows install screen

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Level 1

8 points

Disk formatting problems when on windows install screen

Hello,

I've been really frustrated for the better half of a year now with this issue.

I'm using an iMac, Sierra.

About two or three years ago, I was able to successfully dual boot Windows on this machine. However, about half a year ago I was being an idiot and messed with AMD drivers on Windows. Unfortunately, this bricked my graphics drivers and caused (to my knowledge) an unfixable black screen.

I decided it was time to delete my Windows disk and start anew, so I headed onto mac bootup and deleted the Windows partition. However, when I tried to re-install Windows, I kept getting an error stating Windows could not be installed on the selected disc because of some-sort of NTFS issue.

Well I read a lot of posts, and a huge portion of them were telling people to just hit format on the installation screen when you have the disc selected, so I did that.

Big mistake.

This ended up completely wiping my drives, and somehow separating the fusion drive as well, so I spent a long time re-installing OSX, re-fusing the drive, and trying four or five more times to get windows on my device to no avail. Each time I had to sit through multiple hours for osx to re-install.

I eventually gave up, but I'm back now and really want windows back, but I'm suuuper not in the mood to lose all my documents and such again, and the time machine thing is too confusing for me so I'm going to abstain from using it.

I was just wondering if anyone at all could help me out with this problem, because I'm losing my **** mind over it.

Result of "sudo gpt -r -vv show disk0":

gpt show: disk0: mediasize=24002560000; sectorsize=4096; blocks=5860000

gpt show: disk0: PMBR at sector 0

gpt show: disk0: Pri GPT at sector 1

gpt show: disk0: Sec GPT at sector 5859999

start size
index
contents

0 1 PMBR

1 1 Pri GPT header

2 4 Pri GPT table

6 76800 1
GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

76806
5750421 2
GPT part - 53746F72-6167-11AA-AA11-00306543ECAC

5827227 32768 3
GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

5859995 4 Sec GPT table

5859999 1 Sec GPT header

All other partitions and boot discs are wiped from my device, and it's pretty much as the day it was bought it, yet I can't get this to work even though I got it within minutes the first time I booted windows onto the machine.

Super frustrating.

Thanks,

Mike.

iMac with Retina 5K display

Posted on Dec 12, 2017 2:03 PM

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Answer 1

Best reply

Loner T

Level 9

59,471 points

Dec 13, 2017 1:54 PM in response to USMCRotmg

If you see that error message, and remove attached storage, you should also run

How to reset the System Management Controller (SMC) on your Mac - Apple Support

How to reset NVRAM on your Mac - Apple Support

before the next attempt.

Neither of these procedures change any on-disk information.

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Answer 2

USMCRotmg Author

Level 1

8 points

Dec 13, 2017 3:59 AM in response to Loner T

2015 iMac Retina, I believe.

/dev/disk0 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 24.0 GB disk0

1: EFI EFI 314.6 MB
disk0s1

2: Apple_CoreStorage Fusion 23.6 GB disk0s2

3: Apple_Boot Boot OS X 134.2 MB
disk0s3

/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk1

1: EFI EFI 209.7 MB
disk1s1

2: Apple_CoreStorage Fusion 999.3 GB
disk1s2

3: Apple_Boot Recovery HD 650.0 MB
disk1s3

/dev/disk2 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Fusion +1.0 TB disk2

Logical Volume on disk0s2, disk1s2

E68D6263-88EE-4BC8-B747-6D87BFBB7237

Unencrypted Fusion Drive

I do not have a time machine backup, and I don't really care to make a backup.

Thanks for the response!

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Answer 3

Loner T

Level 9

59,471 points

Dec 13, 2017 4:02 AM in response to USMCRotmg

The Fusion drive configuration looks fine. If you are able to see a BOOTCAMP partition on the 1TB disk when using BC Assistant to install Windows, it may just be a formatting issue, because older macOS versions/Macs can only create a FAT32 partition, which must be formatted to NTFS before Windows can be installed. It would be very helpful to see the exact error message.

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Answer 4

USMCRotmg Author

Level 1

8 points

Dec 13, 2017 4:11 AM in response to Loner T

Well, it doesn't create the BOOTCAMP partition until I start the Windows installation.

Unfortunately, I don't have an ISO on hand, and I would have to get back to you if you really need to see the message text.

I understand how my vague recount of what the error message said might not be too helpful, but really, I'm pretty certain all it said was that the selected disk isn't NTFS and that it needs to be formatted to NTFS. Only problem is, if I use the "format" option on the bootcamp partition while trying to install windows, my entire machine's drive gets wiped.

I believe I even went into the Windows installation command line did some poking around with the disk too, to no avail.

Any ideas?

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Answer 5

Loner T

Level 9

59,471 points

Dec 13, 2017 5:22 AM in response to USMCRotmg

Is BCA failing to create the partition? You can get the ISO from Download Windows 10 Disc Image (ISO File) assuming you want to install W10.

On a Fusion drive the default partition should be a BOOTCAMP on the 1TB disk. You may have to scroll in the installation partition window to see it.

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Answer 6

USMCRotmg Author

Level 1

8 points

Dec 13, 2017 1:20 PM in response to Loner T

OK so I got back to the installation screen, and now I'm getting an error claiming the installer cannot create a partition when I select the BOOTCAMP disk.

I no longer get the NTFS error, and bootcamp now properly makes the partition ntfs automatically.

Gyazo - 4c8ef4fbd2929b6e68da1d0c78bfca8c.png

I'm so close to being able to install Windows, crossing my fingers and hoping you can help me!

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Answer 7

Loner T

Level 9

59,471 points

Dec 13, 2017 1:24 PM in response to USMCRotmg

Are you getting an error listed in If you see a partition alert while using Boot Camp to install Windows - Apple Support ?

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Answer 8

Loner T

Level 9

59,471 points

Dec 13, 2017 3:55 AM in response to USMCRotmg

What is the year/model of iMac? Can you post the output of

diskutil list

Do you have a Time Machine backup of macOS?

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Answer 9

USMCRotmg Author

Level 1

8 points

Dec 13, 2017 1:26 PM in response to Loner T

Yes, and I removed all connections except for keyboard/mouse considering I need them to install, but the message still appears.

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Answer 10

USMCRotmg Author

Level 1

8 points

Dec 13, 2017 2:27 PM in response to Loner T

I want to formally thank you for your assistance. This final step was all I needed, and I'm downloading software on my new windows 10 bootup now after a year of frustration, thanks to you.

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Answer 11

Loner T

Level 9

59,471 points

Dec 13, 2017 2:29 PM in response to USMCRotmg

Excellent. Please backup macOS, Windows and create a Windows System Restore point, for your own sanity and future recovery.

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Answer 12

Loner T

Level 9

59,471 points

Dec 13, 2017 2:31 PM in response to USMCRotmg

Also, if you work for the US Armed Forces, Thank You for your service. ✅

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