Late 2015 iMac and 1TB fusion Bootcamp experience

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Level 1

20 points

Late 2015 iMac and 1TB fusion Bootcamp experience

Hello Gang,

I had a whopping fun time getting Windows 10 installed and wanted to share my workaround.

For some reason Windows would not install with bootcamp. Something about the partition could not be found after formatting the BOOTCAMP partition. So I deleted and recreated the partition to help the OS find it... right? Bad idea 😁. Oh Windows installed and it also nuked my OS X install.

This left me without a fusion drive after command + r restore of the OS. I basically had two separate disks (1TB and 24GB SSD) vs. the logical fusion drive. Well the following 3rd party blog thankfully helped me recreate the Fusion Drive called "How to make your own fusion drive". So now I am back to the factory settings placing the SSD partition first and Spindle second in my logical volume group.

Round two with bootcamp and Windows 10 64 bit. Great success! This is my workaround.

Create a good time machine backup just in case you need to restore the system back to defaults.

Leverage the "Repair Windows" option from the boot camp when Windows install began.

Choose troubleshoot

Advanced options: command prompt

Use DISKPART from the CMD prompt to format the BOOTCAMP partition as NTFS.

Here is where I am going off of memory and the help files in disk part.

List disk" brought me to disk 0

"select disk 0"

"List Partition" showed me BOOTCAMP on partition 5.

"select partition 5”

then I did something like “format FS=NTFS LABEL=BOOTCAMP QUICK

Exit Disk Part after the formatting and run setup.exe from the root of X:Sources

Wallah! The install went without a hitch. Boot Camp post-install worked like a champ.

Hopefully this will help anyone who runs into a similar issue installing Windows 10 and bootcamp.

Posted on Nov 22, 2015 10:56 PM

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Answer 1

larspj

Level 1

13 points

Nov 22, 2015 11:43 PM in response to Bryan Debnam

i Will try this out.

did you boot up with the EFI? Or just normal Windows? And did you get the Windows installer to format the partition first?

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Answer 2

Bryan Debnam Author

Level 1

20 points

Dec 12, 2015 6:58 PM in response to larspj

Hi there. I basically followed the normal boot camp steps then choose repair instead of the standard install and formatting via GUI.

I partitioned the "boot camp" with dispart and left the other partitions in tact.

Next I ran setup.exe from the command like. This is picking up where we would normally have started with bootcamp.

I hope that makes sense. If you are in a bind I could try to help you over FaceTime one weekend on a phone or iPad.

Cheers!

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Answer 3

Loner T

Level 9

59,536 points

Dec 12, 2015 7:07 PM in response to Bryan Debnam

The diskpart usage is dangerous with Fusion drives as you found out. The closest I recommend is to convert the FAT32 created by BCA to be erased and left as Free Space, which avoids all issues. If you leave external storage attached or break the Fusion drive, you can spend hours/days restoring TM backups.

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Answer 4

Bryan Debnam Author

Level 1

20 points

Dec 12, 2015 10:24 PM in response to Loner T

Disk part was not dangerous for the record. Deleting the partition via the GUI during the normal Boot Camp setup is destructive. Formatting the Boot Camp Partition was easy breezy. Just don't nuke the whole partition in any form or fashion (EFI and so on). Also if BCA is working this write-up is not for you. BCA would not format at all during the traditional setup for me. It gave an error. I wish boot camp had functioned as it has so many times before on other hardware 🙂.

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Answer 5

Loner T

Level 9

59,536 points

Dec 13, 2015 6:19 AM in response to Bryan Debnam

Can you describe the issues with BCA? Boot Camp: "We couldn't create a new partition or locate an existing one" alert during Windows 8 install - Apple Support is a very common issue and can be easily addressed. If you saw something more esoteric, it would be worth duplicating addressing.

Diskpart, if not used carefully, creates an EFI (104MB) which is smaller than that of the Mac (209MB) and causes quite a bit of heartburn.

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