Starting into Win 10 boot camp now shows "missing operating system" after bless commands

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Level 1

4 points

Starting into Win 10 boot camp now shows "missing operating system" after bless commands

Had managed to configure a 2012 MBP with a triple boot: El Capitan 10.11.6, Windows 10, Budgie 20.04 (Ubuntu Linux Flavor). All was working, but Windows showed no custom icon, and Budgie had no custom icon or name. Got into the EFI partition with some bless commands and got Budgie's icon customized but not its name. Oh well. Now when I boot to Windows, either via Startup Manager or the Startup Disk conrol panel, I get "missing operating system".

I tried booting from a Windows USB stick and it doesn't see any other operating systems as available to repair. If I select my Windows drive in the Startup Disk control panel to attempt another failed Windows boot, on next Mac boot, the Windows drive no longer appears in the control panel. If I mount the Windows partition, it appears again, but no better. It always appears in Startup Manager. I tried replacing the BOOT folder in the EFI partition with an old backup, but no help. No partition structures were changed, and Windows drive itself seems in tact. Anybody know what went wrong or how to fix it?

Based on this thread, here are some relevant dumps, but as my drive layout is different than the examples I saw, I don't know what fsck commands to attempt next. "Mayan" is my Mac boot, "id10t" is my Win 10 boot, disk0s6 is the linux boot.

Terminal Output

@Loner T, any help?

MacBook Pro 15″, OS X 10.11

Posted on Sep 21, 2025 2:26 PM

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Answer 1

HWTech

Level 9

67,130 points

Sep 22, 2025 6:46 PM in response to msyeed

Unfortunately I haven't seen @LonerT post anything in many years now.

What bless commands did you use in your attempts to customize the names & icons?

It has been a few years since I last tried to customize a boot disk. From what I recall, you need to store the icon picture into a hidden file on the root of the boot volume called

.VolumeIcon.icns

It must meet certain specifications. I can try checking one of my custom boot drives tomorrow to see if I can confirm this.

As for the name seen on the Option Boot Apple boot picker menu, that can be a bit more complicated. You must use the bless "-label" option since the text will be converted into an image. I have had mixed luck with this over the years especially when using the drive on different Macs. IIRC, the following is the command I used, just make sure the hidden EFI partition is mounted as writeable before using the command:

sudo  bless  --folder  /Volumes/EFI/EFI/budgie  --label "Budgie"  --shortform

As for your Windows boot issue....it is hard to say what happened especially without knowing all of the bless commands you used (and any others such as the gpt command). You can try creating a bootable rEFInd USB stick to see whether rEFInd can see your Windows installation & boot from it. IIRC, it is easy to make a bootable rEFInd USB stick by using the rEFInd .img file as a source for Etcher (Mac, Windows, Linux). I also think it can be made by copying the contents of the rEFInd .img file to a FAT32 formatted USB stick, but I'm not certain.

The last couple of times I tried to fix a non-booting Windows system (dedicated Windows PC).....I was unsuccessful which is unusual for me, but it was with later versions of Windows (I think MS had changed something by then, and now Win10 has made it even more difficult). I know Windows has (or used to have) a special utility to configure the boot options on Windows, but the resulting file can be edited in any text editor as well (back up the original first). Between your Windows USB, Budgie, and rEFInd (perhaps even macOS)....you should be able to check out the Windows boot configuration file to see if it is correct. The best option is to have Windows use its automatic boot repair utility to fix things as it should correct for any partition changes or bootloader changes (such as changing the file(s) on the hidden EFI partition).

I know that both rEFInd and Grub2 should allow you to attempt to jump start into the Windows bootloader, but there are multiple .efi files on Windows (one is the real Windows bootloader, another used to be for Windows recovery mode (forget what it was really called), and IIRC there were several others all with the same or nearly same names. Last time I tried to jumpstart the Windows bootloader I was unsuccessful and I have no idea why.

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Answer 2

msyeed Author

Level 1

4 points

Sep 22, 2025 8:36 PM in response to HWTech

For the icon, yeah, I just pasted the desired Budgie icon on the EFI partition in Get Info, since that's where Grub is installed, and that worked. For the name, I tried your version of the bless command, less the shortform flag, but adding it didn't do it either. I also tried:

sudo  bless  --folder  /Volumes/EFI/EFI   --file  /Volumes/EFI/EFI/ubuntu/grub.efi  --label  "Budgie"  --verbose
sudo  bless  --device  /dev/disk0s1   --file  /Volumes/EFI/EFI/ubuntu/grub.efi  --label  "Budgie"  --verbose

All of them created the expected files in the appropriate folders, but nothing affected the startup manager.

For the Windows partition, I manually placed a .VolumeIcons.icns at the root level of the Windows partition years ago. Didn't work, but did no harm. Once I realized the Mac bootloader was still checking a folder on the EFI volume, I decided, what the ****, and put a .VolumeIcons.icns in its boot folder, which bootcamp had cleverly named BOOT. No go.

It was around here I actually tested the boots instead of just looking to see if the cosmetic results worked, and realized Windows was broken, giving the "missing operating system" result.

I don't know my way around DOS, so what I ran was minimal. Booting into the USB stick's command line, I ran:

bootrec /FixMbr (successful, but no indication on what)
bootrec /FixBoot (could not run)
bootrec /ScanOs (found no operating systems)
bootrec /RebuildBcd (found no operating systems)

I detailed the gpt commands I ran via gdisk in my previous post, which changed the hybrid MBR to a protective MBR. Now the startup manager couldn't see the Windows volume, but bootrec could. FixBoot still wouldn't run (research says possibly a BIOS vs UEFI environment problem?) but ScanOS and RebuildBcd worked. The stick now for the fist time gave me the option to continue onto the Windows 10 environment...but it just rebooted back to the Starup Manager with no Windows option.

I have a feeling I need to recreate the hybrid MBR as in this article but I need a little guidance -- don't wanna bork my entire drive. And if that gets me back to where I was when I first posted this article, I think next would be to run fdisk as in this answer, but customized to my drive/partition situation.

sudo fdisk -e /dev/disk0
p
setpid 4
07
flag 4
p
w
y

Any hope? Sorry about the delay in responding -- the site isn't notifying me when the thread updates.

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Answer 3

msyeed Author

Level 1

4 points

Sep 21, 2025 7:01 PM in response to msyeed

The site locked me out for a good long time, but here's Part 2 of 2:

mayan:~ msyeed$ sudo gpt -vv -r show /dev/disk0
Password:
gpt show: /dev/disk0: mediasize=960197124096; sectorsize=512; blocks=1875385008
gpt show: /dev/disk0: Suspicious MBR at sector 0
gpt show: /dev/disk0: Pri GPT at sector 1
gpt show: /dev/disk0: Sec GPT at sector 1875385007
       start        size  index  contents
           0           1         MBR
           1           1         Pri GPT header
           2          32         Pri GPT table
          34           6         
          40      409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
      409640  1367851144      2  GPT part - 53746F72-6167-11AA-AA11-00306543ECAC
  1368260784     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  1369530320          48         
  1369530368    15626240      4  GPT part - 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F
  1385156608    99604480      6  GPT part - 0FC63DAF-8483-4772-8E79-3D69D8477DE4
  1484761088   390623232      5  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  1875384320         655         
  1875384975          32         Sec GPT table
  1875385007           1         Sec GPT header
mayan:~ msyeed$ sudo fdisk /dev/disk0
Disk: /dev/disk0	geometry: 116737/255/63 [1875385008 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE    0   0   1 - 1023 254  63 [         1 -     409639] <Unknown ID>
*2: DA 1023 254  63 - 1023 254  63 [    409640 - 1367851144] <Unknown ID>
 3: AF 1023 254  63 - 1023 254  63 [1368260784 -    1269536] HFS+        
 4: 82 1023 254  63 - 1023 254  63 [1369530368 -   15626240] Linux swap  
mayan:~ msyeed$ sudo dd if=/dev/rdisk0s5 count=1 2>/dev/null | hexdump -C
00000000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00  |.R.NTFS    .....|
00000010  00 00 00 00 00 f8 00 00  3f 00 ff 00 00 a8 7f 58  |........?......X|
00000020  00 00 00 00 80 00 80 00  ff 6f 48 17 00 00 00 00  |.........oH.....|
00000030  00 00 0c 00 00 00 00 00  02 00 00 00 00 00 00 00  |................|
00000040  f6 00 00 00 01 00 00 00  57 81 a8 dc 9d a8 dc 8e  |........W.......|
00000050  00 00 00 00 fa 33 c0 8e  d0 bc 00 7c fb 68 c0 07  |.....3.....|.h..|
00000060  1f 1e 68 66 00 cb 88 16  0e 00 66 81 3e 03 00 4e  |..hf......f.>..N|
00000070  54 46 53 75 15 b4 41 bb  aa 55 cd 13 72 0c 81 fb  |TFSu..A..U..r...|
00000080  55 aa 75 06 f7 c1 01 00  75 03 e9 dd 00 1e 83 ec  |U.u.....u.......|
00000090  18 68 1a 00 b4 48 8a 16  0e 00 8b f4 16 1f cd 13  |.h...H..........|
000000a0  9f 83 c4 18 9e 58 1f 72  e1 3b 06 0b 00 75 db a3  |.....X.r.;...u..|
000000b0  0f 00 c1 2e 0f 00 04 1e  5a 33 db b9 00 20 2b c8  |........Z3... +.|
000000c0  66 ff 06 11 00 03 16 0f  00 8e c2 ff 06 16 00 e8  |f...............|
000000d0  4b 00 2b c8 77 ef b8 00  bb cd 1a 66 23 c0 75 2d  |K.+.w......f#.u-|
000000e0  66 81 fb 54 43 50 41 75  24 81 f9 02 01 72 1e 16  |f..TCPAu$....r..|
000000f0  68 07 bb 16 68 52 11 16  68 09 00 66 53 66 53 66  |h...hR..h..fSfSf|
00000100  55 16 16 16 68 b8 01 66  61 0e 07 cd 1a 33 c0 bf  |U...h..fa....3..|
00000110  0a 13 b9 f6 0c fc f3 aa  e9 fe 01 90 90 66 60 1e  |.............f`.|
00000120  06 66 a1 11 00 66 03 06  1c 00 1e 66 68 00 00 00  |.f...f.....fh...|
00000130  00 66 50 06 53 68 01 00  68 10 00 b4 42 8a 16 0e  |.fP.Sh..h...B...|
00000140  00 16 1f 8b f4 cd 13 66  59 5b 5a 66 59 66 59 1f  |.......fY[ZfYfY.|
00000150  0f 82 16 00 66 ff 06 11  00 03 16 0f 00 8e c2 ff  |....f...........|
00000160  0e 16 00 75 bc 07 1f 66  61 c3 a1 f6 01 e8 09 00  |...u...fa.......|
00000170  a1 fa 01 e8 03 00 f4 eb  fd 8b f0 ac 3c 00 74 09  |............<.t.|
00000180  b4 0e bb 07 00 cd 10 eb  f2 c3 0d 0a 41 20 64 69  |............A di|
00000190  73 6b 20 72 65 61 64 20  65 72 72 6f 72 20 6f 63  |sk read error oc|
000001a0  63 75 72 72 65 64 00 0d  0a 42 4f 4f 54 4d 47 52  |curred...BOOTMGR|
000001b0  20 69 73 20 63 6f 6d 70  72 65 73 73 65 64 00 0d  | is compressed..|
000001c0  0a 50 72 65 73 73 20 43  74 72 6c 2b 41 6c 74 2b  |.Press Ctrl+Alt+|
000001d0  44 65 6c 20 74 6f 20 72  65 73 74 61 72 74 0d 0a  |Del to restart..|
000001e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000001f0  00 00 00 00 00 00 8a 01  a7 01 bf 01 00 00 55 aa  |..............U.|
00000200
mayan:~ msyeed$

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Answer 4

msyeed Author

Level 1

4 points

Sep 21, 2025 2:27 PM in response to msyeed

Here's that terminal output, code formatted, and split up to appease the character limit

mayan:~ msyeed$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *960.2 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage Mayan                   700.3 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:                 Linux Swap                         8.0 GB     disk0s4
   5:       Microsoft Basic Data id10t                   200.0 GB   disk0s5
   6:           Linux Filesystem                         51.0 GB    disk0s6
/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Mayan                  +700.0 GB   disk1
                                 Logical Volume on disk0s2
                                 5F88217A-6F4F-4864-8235-F93F828EA81D
                                 Unlocked Encrypted
mayan:~ msyeed$ diskutil cs list
CoreStorage logical volume groups (1 found)
|
+-- Logical Volume Group FE47B2A2-BA4B-4B69-84CF-A523E1A06C3F
    =========================================================
    Name:         Mayan
    Status:       Online
    Size:         700339785728 B (700.3 GB)
    Free Space:   0 B (0 B)
    |
    +-< Physical Volume 0C9895C1-5404-4CC7-9EBD-A1511B583E2F
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     700339785728 B (700.3 GB)
    |
    +-> Logical Volume Family 875329CF-F943-461B-B3E9-92101541DCEE
        ----------------------------------------------------------
        Encryption Type:         AES-XTS
        Encryption Status:       Unlocked
        Conversion Status:       Complete
        High Level Queries:      Fully Secure
        |                        Passphrase Required
        |                        Accepts New Users
        |                        Has Visible Users
        |                        Has Volume Key
        |
        +-> Logical Volume 5F88217A-6F4F-4864-8235-F93F828EA81D
            ---------------------------------------------------
            Disk:                  disk1
            Status:                Online
            Size (Total):          699999977472 B (700.0 GB)
            Revertible:            Yes (unlock and decryption required)
            LV Name:               Mayan
            Volume Name:           Mayan
            Content Hint:          Apple_HFS

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Answer 5

msyeed Author

Level 1

4 points

Sep 21, 2025 8:35 PM in response to msyeed

Aaaaand I thought I had a breakthrough when I saw the MBR was "suspicious", did some digging, and did this:

[Launched gdisk /dev/disk0]
Typed x to enter experts' mode.
Typed n to create a new protective MBR.
Typed 'w` to save your changes.
Typed y to confirm that you want to save the changes.

Aaaand now the MBR partition shows up as a PMBR, and the bootcamp partition doesn't show up in Startup Manager anymore. I was now, however, able to find the partition and run Windows system recovery on it from my USB boot. Although it "succeeded" it did nothing, and now I'm back to Windows recovery not seeing the volume. I can get Startup Disk to see it, but if I select it, on reboot I'm just dumped back into macOS. Falling further in...

If I could get back to where I was yesterday, I'd be thrilled: Windows or Mac selectable via Startup Disk, three working volumes showing when booting into Startup Manager: Mayan (macOS), Windows, Boot EFI (grub into Budgie).

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