Q: 2015 iMac Boot Camp not working giving "We couldn't create a new partition error..."

Yes it allows me to format. I haven't done it yet because I know that you can't undo it. Do you want me to format and send you the results? I've formated in the window installer in the past and it hasn't fixed the problem.

Sorry for so much of the back and forth.

When i did the gdisk steps i sent you, i conducted the changes on disk1. The steps were just for a non fusion mac so I adjusted to disk 1 given the fusion drive.

My mac isn't a retina display iMac but it is from last year just before the retina iMacs were released so it shouldn't be too old.

I don't care what steps to take, I'll do whatever you think is best though when I conducted the gdisk steps I listed on the fusion disk 1, it stopped giving me the ntsf warning but gave a different error that wouldn't let me install, even after formatting the disk via the windows installer. It also gave an error at the end when i tried to save the gdisk changes (step 13) that said that it could not access rdisk1.

If you have a method that you've tested on fusion macs before, I'm willing to try it. Right now I'm just sitting on the partition post BCA setup. Am a bit afraid to make any huge changes cause I know it's easy to set it up wrong.

Here's the about this mac. I create the MBR via the Boot Camp Assistant correct? or do I do it with the steps

For reference the Gdisk steps I have seem to be to set up a GPT setup.

http://macriot.com/mcrt/?p=2362

Sorry last note. This is what I found to build a MBR but it seems to require that I do it in the window's installer. Does this seem sound? (via: http://superuser.com/questions/481650/cant-use-bootcamp-partition-for-windows-8- installation)

Here my steps:

1. Start the install and go to the partition selection screen
2. Press Shift+F10 to open a command prompt window
3. Execute the following commands:

   diskpart select disk 0 (assuming 0 is the disk where you created the bootcamp partition) select partition 4 (assuming 4 is your bootcamp partition) format fs=NTFS label="Windows 8" (I didn’t use QUICK) exit exit 

4. Press refresh and you should be able to select the partition.

This solution doesn't seem to work when booting from the bootcamp created USB. I managed to make it work by buying a USB SuperDrive and booting from the Windows disk (not EFI). Worked like magic after that. Also quick format works too - will save you 2 hours on a 1TB disk.

I followed the steps here (http://macriot.com/mcrt/?p=2362). Now the error is no longer NTSF related. It's simply saying

"We couldn't create a new partition or locate an existing one. For more information, see the Setup log files"

If you'd like I can send the read outs from terminal again.

The process was listed below. and the new P and O read outs are below.

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

NOTE: Write test failed with error number 1. It will be impossible to save

changes to this disk's partition table!

You may need to deactivate System Integrity Protection to use this program. See

https://www.quora.com/How-do-I-turn-off-the-rootless-in-OS-X-El-Capitan-10-11

for more information.

Partition table scan:

  MBR: protective

  BSD: not present

  APM: not present

  GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): P

Disk /dev/disk1: 5860533168 sectors, 2.7 TiB

Logical sector size: 512 bytes

Disk identifier (GUID): AC39F17B-8E64-442F-B254-ABF8AE371DA6

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 5860533134

Partitions will be aligned on 8-sector boundaries

Total free space is 1805 sectors (902.5 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name

   1              40          409639   200.0 MiB   EF00  EFI System Partition

   2          409640      3904445575   1.8 TiB     AF05  Internal Drive

   3      3904445576      3905715335   620.0 MiB   AB00  Recovery HD

   4      3905716224      5860532223   932.1 GiB   0700  BOOTCAMP

Command (? for help): x

Expert command (? for help): n

Expert command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING

PARTITIONS!!

Do you want to proceed? (Y/N): Y

OK; writing new GUID partition table (GPT) to /dev/disk1.

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

Unable to open device '/dev/disk1' for writing! Errno is 1! Aborting write!

Expert command (? for help):

-----

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

NOTE: Write test failed with error number 1. It will be impossible to save

changes to this disk's partition table!

You may need to deactivate System Integrity Protection to use this program. See

https://www.quora.com/How-do-I-turn-off-the-rootless-in-OS-X-El-Capitan-10-11

for more information.

Partition table scan:

  MBR: protective

  BSD: not present

  APM: not present

  GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): P

Disk /dev/rdisk1: 5860533168 sectors, 2.7 TiB

Logical sector size: 512 bytes

Disk identifier (GUID): AC39F17B-8E64-442F-B254-ABF8AE371DA6

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 5860533134

Partitions will be aligned on 8-sector boundaries

Total free space is 1805 sectors (902.5 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name

   1              40          409639   200.0 MiB   EF00  EFI System Partition

   2          409640      3904445575   1.8 TiB     AF05  Internal Drive

   3      3904445576      3905715335   620.0 MiB   AB00  Recovery HD

   4      3905716224      5860532223   932.1 GiB   0700  BOOTCAMP

Command (? for help): O

This option deletes all partitions and creates a new protective MBR.

Proceed? (Y/N): N

Command (? for help): R

Recovery/transformation command (? for help): O

Disk size is 5860533168 sectors (2.7 TiB)

MBR disk identifier: 0x00000000

MBR partitions:

Number  Boot  Start Sector   End Sector   Status      Code

   1                     1   4294967294   primary     0xEE

Recovery/transformation command (? for help):

Thanks. I booted locally and removed the SIP. The process completed successfully.

It's still giving me the "We Couldn't Create a New Partition or locate an existing one. For more Information, see the Setup Log files"

Do you think it's my USB drive? It's just a standard kingston traveler. I do have a USB disk drive though and could try installing directly from the disk.

Again thanks for all the patience. I know it's been a pain.

The kingston is 15gigs. It is just a standard USB thumb drive. It is a bit old though. It's set to FAT not Ex FAT and it was set to a Master Boot Record via disk utility.

I reset the SMC and the NVRAM with all the USBs removed and tried booting from the EFI thumb drive again. It is giving me the same error. I will post the fdisk rundown in a second.

here is the results of the sudo command.

sudo fdisk /dev/disk1

Password:

Disk: /dev/disk1 geometry: 97451/255/63 [1565565872 sectors]

Signature: 0xAA55

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

1: EE    0   0   2 - 1023 255  63 [         1 - 4294967295] <Unknown ID>

2: 00    0   0   0 -    0   0   0 [         0 -          0] unused     

3: 00    0   0   0 -    0   0   0 [         0 -          0] unused     

4: 00    0   0   0 -    0   0   0 [         0 -          0] unused     

Christophers-iMac:~ christopherwoodside$