Need help with Disk utility and bootcamp-related problems.

[maxmaut]

I need to install Windows on my 5k iMac. I started with bootcamp, and created a partition, but for some reason Windows did now want to get installed there. The problem was with the partition, and I found an article saying I need to delete BOOTCAMP partition from windows install interface and then install windows into empty space on the drive, which I did try.

After that windows did not install, saying there is a problem with GPT/MBR partitions, and I went through this answer on superuser which did not help me install windows either.

Then, I ended up with a couple of empty partitions, big and small. This is current partition map:

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

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 879315167 419.1 GiB AF00 Diagnostics

3 879315168 881244159 941.9 MiB AB00 Recovery HD

4 881506304 881711103 100.0 MiB EF00 EFI system partition

5 881711104 881743871 16.0 MiB 0C01 Microsoft reserved ...

6 882665472 882870271 100.0 MiB EF00 EFI system partition

7 882870272 883791871 450.0 MiB 2700 Basic data partition

8 883791872 883996671 100.0 MiB EF00 EFI system partition

9 883996672 884918271 450.0 MiB 2700 Basic data partition

10 884918272 885123071 100.0 MiB EF00 EFI system partition

11 885123072 976842879 43.7 GiB AF00 Apple_HFS_Untitled_2


The worst thing is that Disk Utility does not let me delete these small partitions. When I select them, the "minus" button is just grayed out.

I decided to do a complete wipe of the drive and restore from time machine, but now, every time I make a bootable El Capitan thumb via createinstallmedia, when I try loading from it all I see is a crossed circle (as if the thumb is empty).

Any idea what I might have broken in order to cause this happening?

Thanks!

 

[Shirasaki]

Although I don't know how to answer your question, does your iMac use fusion drive?

 

[JohnDS]

I believe those small partitions are part of the system and need to be there.

Before you ran createinstallmedia, did you use disk utility to reformat your thumb drive to Apple Extended Format (Journalled). If not, do so, then go to Partition, partition it as one partition and hit the Options tab to make sure the partition map is GUID. Then retry createinstallmedia.

 

[maxmaut]

Although I don't know how to answer your question, does your iMac use fusion drive?

It's a single SSD.

I believe those small partitions are part of the system and need to be there.

Before you ran createinstallmedia, did you use disk utility to reformat your thumb drive to Apple Extended Format (Journalled). If not, do so, then go to Partition, partition it as one partition and hit the Options tab to make sure the partition map is GUID. Then retry createinstallmedia.

Yes, I do format the thumb drive prior to using createinstallmedia, but every time I actually run createinstallmedia it wants to format the drive itself again.

 

[Shirasaki]

It's a single SSD.

If so then it just looks strange. No need to create so many EFI partition anyway.
Apple Disk Utility is not that aggressive when formatting drives. Maybe you need the help of command line tools.
With so many EFI partitions, there is no wonder why installer does not want to install OS onto your partition.

 

[JohnDS]

Is the thumb drive big enough?