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I had macOS and Windows 10 installed through Bootcamp on my Macbook Pro (late 2013) and everything worked fine. Then I tried installing Ubuntu on an external drive and setting up pure-EFI triple boot. However, in the process I accidentally deleted the original EFI folder (not the partition, just the folder) and now the option for Windows doesn't show up when holding down ALT/Option key during startup, though I am able to boot into macOS and Ubuntu without problem. I noticed the EFI folder in /dev/disk0s1/ (the EFI partition) has only an APPLE folder but is missing the Microsoft one. I wonder if there is a way to recover the EFI files/entries and fix this problem so I can boot into Windows again?

If I remember correctly, I deleted the original EFI folder by doing this in Ubuntu:

$ sudo mkdir -p /mnt/sda1
$ sudo mount /dev/sda1 /mnt/sda1
$ sudo rm -r /mnt/sda1/EFI

Now when I boot into macOS, I can still see the BOOTCAMP partition with my Windows files on it. Also, System Preferences-->Startup Disk still recognizes two System, the macOS and the "BOOTCAMP Windows". However, selecting the latter and reboot would lead to a black screen with error message reading "No bootable device found."

In macOS, typing diskutil list returns this:

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *251.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                 Apple_APFS Container disk1         164.0 GB   disk0s2
   3:       Microsoft Basic Data BOOTCAMP                86.3 GB    disk0s3
   4:           Windows Recovery                         471.9 MB   disk0s4

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +164.0 GB   disk1
                             Physical Store disk0s2
   1:                APFS Volume Macintosh HD            148.7 GB   disk1s1
   2:                APFS Volume Preboot                 20.7 MB    disk1s2
   3:                APFS Volume Recovery                506.6 MB   disk1s3
   4:                APFS Volume VM                      1.1 GB     disk1s4

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *256.1 GB   disk2
   1:                  Apple_HFS Ubuntu                  536.9 MB   disk2s1
   2:           Linux Filesystem                         131.1 GB   disk2s2
   3:                 Linux Swap                         17.1 GB    disk2s3
   4:       Microsoft Basic Data                         107.4 GB   disk2s4

Is there anything I could do to get back into my Windows system? Many thanks in advance.

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  • FYI, it is possible to do a pure EFI triple boot without the use of an external disk. This is best done using two internal EFI partitions.
    – David Anderson
    Dec 12, 2017 at 4:32

2 Answers 2

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  1. I suppose you will need a Window 10 installer flash drive. If you do not have this flash drive, you will have to build one. First download the 64-bit Windows 10 iso from this Microsoft web site. This can be done while running macOS. Next you will need 16 GB or larger flash drive. For your model Mac, I believe the Boot Camp Assistant will aid in the creation of the Windows installer flash drive. If not, let me know.

  2. If the root folder of the flash drive contains the file AutoUnattend.xml, you will need to rename the file to NoAutoUnattend.xml.

  3. Boot to the flash drive. Hold down the option key at start up. From the Startup Manager, select the icon labeled "EFI Boot".

  4. Open a Windows Command Prompt window, by following the procedure outlined in this step. Below is an image of what is initially displayed by the Windows 10 installer. Select "Next".

    z1

    In the image shown below, select "Repair your computer".

    z2

    In the image shown below, select "Troubleshoot".

    z3

    In the image shown below, select "Command Prompt".

    z4

    The result should be the image shown below.

    z6

  5. Use the diskpart command to determine the drive letter for BOOTCAMP partition.

    diskpart
list volume
exit

  6. Enter the command below to assign drive letter S to the EFI partition.

    mountvol S: /s

  7. Here I will assume the BOOTCAMP partition is assign the drive letter C. Enter the command shown below to recreate the boot files.

    bcdboot C:\windows /s S:

  8. Enter the command shown below, then select option to "Turn off your PC".

    exit
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  • Thanks a lot for this very detailed instruction!!! It worked perfectly for me, and now I actually have a functioning triple-boot setup. Many, many thanks!
    – frogwell
    Dec 12, 2017 at 7:06
  • 3
    In the Windows Setup dialog, you can get straight into a command prompt by pressing Shift-F10.
    – mwfearnley
    May 15, 2020 at 12:51
  • +1 Yes! top dollar to you, Sir @Dave Anderson. This answer worked for me. My case had the added factor of Windows 10 running BitLocker - Microsoft's full disk encryption (FDE) for Windows, which prompts with the password before starting Windows. In the case of Bootcamp, this FDE is only for the Windows C\: drive and the Bitlocker password is asked for directly after clicking on the Bootcamp startup disk icon menu option presented on starting the Mac (with alt key held down). 1 of 2
    – therobyouknow
    Sep 17, 2020 at 22:10
  • 2 of 2: So for my setup with Bitlocker on Windows, I needed to unlock the C: drive before running the bcdboot command in your step 7. The command I used was: manage-bde -unlock D: -Password . I pressed enter then gave it my bitlocker password when it asked Then I proceeded to step 7. References: top-password.com/blog/… and docs.microsoft.com/en-us/windows-server/administration/… If I didn't unlock the bitlocker C: drive, step 7 would fail. So thank you.
    – therobyouknow
    Sep 17, 2020 at 22:12
  • 3 additional helpful notes that add to my previous above 1) After choosing 'Command Prompt' step 4, if, like me, you have a bitlocker encrypted drive, you will be offered to enter your recovery key. But also on that same screen, is 'Skip drive' - I clicked that - which got me to the command window with X:\Sources I then proceeded with remaining steps...
    – therobyouknow
    Mar 27, 2021 at 15:08
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I had macOS and Windows 10 installed through Bootcamp on my iMac (Mid-2011) and everything worked fine. Then I installed a new SSD with no issues. I continued using Windows through the old HDD via Bootcamp. However, in the process of assigning more disk space to Windows, I accidentally deleted the original Macintosh HD. I have since restored it from the recovery boot menu.

The issue I now have is the option for Windows doesn't show up when holding down the Alt/Option key during startup. I can see the Bootcamp partition and Windows files in the Finder, as well as in Disk Utility (although "First Aid" is greyed out). I can also see Bootcamp in the Startup Disk menu.

It seems since recovering the Macintosh HD associated with my Bootcamp partition, it has lost its association. Is it possible it is something to do with the EFI folder being recreated in recovery?

In macOS, typing diskutil list returns this:

#:                       TYPE NAME                    SIZE       IDENTIFIER
0:      GUID_partition_scheme                        *1.0 TB     disk0
1:                        EFI EFI                     209.7 MB   disk0s1
2:                  Apple_HFS Macintosh HD            850.0 GB   disk0s2
3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
4:       Microsoft Basic Data BOOTCAMP                149.2 GB   disk0s4

/dev/disk1 (internal, physical):
#:                       TYPE NAME                    SIZE       IDENTIFIER
0:      GUID_partition_scheme                        *960.2 GB   disk1
1:                        EFI EFI                     209.7 MB   disk1s1
2:                  Apple_HFS Macintosh SSD           959.3 GB   disk1s2
3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3

/dev/disk2 (external, physical):
#:                       TYPE NAME                    SIZE       IDENTIFIER
0:     FDisk_partition_scheme                        *15.5 GB    disk2
1:                 DOS_FAT_32 U                       15.5 GB    disk2s1

/dev/disk3 (internal, physical):
#:                       TYPE NAME                    SIZE       IDENTIFIER
0:                            CCCOMA_X64FRE_EN-US... *5.4 GB     disk3

/dev/disk4 (disk image):
#:                       TYPE NAME                    SIZE       IDENTIFIER
0:     Apple_partition_scheme                        +45.5 MB    disk4
1:        Apple_partition_map                         32.3 KB    disk4s1
2:                  Apple_HFS Floola (MacOS X)        45.4 MB    disk4s2
4:       Microsoft Basic Data                         107.4 GB   disk2s4

Is there anything I could do to get back into my Windows system? I have gone through the steps of this fix and come undone at point 6: It tells me the volume cannot be found.

Many thanks in advance for any assistance.

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  • You should have posted your answer as a new question. You can reference this question in your new question if you wish. The answer I post probably will not work for a 2011 iMac since Windows on 2011 iMac's are suppose to be installed to BIOS boot. BIOS booting does not use the EFI partition. The OP's Mac is a 2013 model which EFI boots Windows.
    – David Anderson
    Mar 27, 2021 at 15:44

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