cfrz
Level 1 (0 points)

Q: Bootcamp Blue Screen winload.efi

For some reason my Windows 8.1 installation has been BSODing on startup, and I'm not sure what caused it.


The error is initially

0xc0000001

And then

0xc000000f "winload.efi missing" once I press enter.

 

Some output:

 

diskutil list:

/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_CoreStorage Macintosh HD            217.4 GB   disk0s2

   3:                 Apple_Boot Recovery HD             650.1 MB   disk0s3

   4:       Microsoft Basic Data                         32.8 GB    disk0s4

/dev/disk1 (internal, virtual):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:                  Apple_HFS Macintosh HD           +217.0 GB   disk1

                                 Logical Volume on disk0s2

                                 7055B8CA-1226-4AA8-946E-6CD9A464E79B

                                 Unlocked Encrypted


sudo gpt -r show /dev/disk0

      start       size  index  contents

          0          1         PMBR

          1          1         Pri GPT header

          2         32         Pri GPT table

         34          6        

         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

     409640  424516304      2  GPT part - 53746F72-6167-11AA-AA11-00306543ECAC

  424925944    1269760      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

  426195704       1288        

  426196992   64036864      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

  490233856        863        

  490234719         32         Sec GPT table

  490234751          1         Sec GPT header


sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 30515/255/63 [490234752 sectors]

Signature: 0xAA55

         Starting       Ending

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

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

1: EE 1023 254  63 - 1023 254  63 [         1 -  490234751] <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     

 

I'm really not sure what's going on and any help is much appreciated.

MacBook Pro (Retina, 15-inch, Mid 2014)

Posted on Jan 24, 2016 8:45 PM

by Loner T,Solvedanswer
Loner T Loner T
Level 7 (24,202 points)
Safari
A:

From https://support.microsoft.com/en-us/kb/927392, you will need to use S: (assigned to EFI) and the appropriate directory within the EFI partition instead of C: shown in the following set of steps. Please see Can't resize Macintosh HD partition as an example of the EFI structure.

 

/RebuildBcd

This option scans all disks for installations that are compatible with Windows Vista or Windows 7. Additionally, it lets you select the installations that you want to add to the BCD store. Use this option when you must completely rebuild the BCD store.

 

Note Use the Bootrec.exe tool to troubleshoot a "Bootmgr Is Missing" error. If rebuilding the BCD store doesn't resolve the startup issue, you can export and delete the BCD store and then run this option again. By doing this, you make sure that the BCD store is completely rebuilt.

 

To do this, type the following commands at the Windows RE command prompt:

  • bcdedit /export C:\BCD_Backup
  • c:
  • cd boot
  • attrib bcd -s -h -r
  • ren c:\boot\bcd bcd.old
  • bootrec /RebuildBcd

Posted on Jan 26, 2016 6:55 AM

Close
cfrz

Q: Bootcamp Blue Screen winload.efi

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  • Helpful answers

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  • by Loner T,Helpful

    Loner T Loner T Jan 27, 2016 5:16 AM in response to cfrz
    Level 7 (24,202 points)
    Safari
    Jan 27, 2016 5:16 AM in response to cfrz

    Can you report the output of the DD command? You can also try to get to command line and try to rebuildBCD.

  • by cfrz,

    cfrz cfrz Jan 25, 2016 10:47 PM in response to Loner T
    Level 1 (0 points)
    Jan 25, 2016 10:47 PM in response to Loner T

    Screen Shot 2016-01-26 at 3.45.39 PM.png

    I can't rebuild the BCD from my recovery USB, saying "the requested system device could not be found", even though /scanOS reports windows being found. Also, what is the mysterious message in the partition header?

  • by Loner T,Helpful

    Loner T Loner T Jan 27, 2016 5:16 AM in response to cfrz
    Level 7 (24,202 points)
    Safari
    Jan 27, 2016 5:16 AM in response to cfrz

    You will need to assign a drive letter to the EFI partition. The Microsoft directory on the EFI partition contains the BCD. The EFI partition is your S device.

  • by cfrz,

    cfrz cfrz Jan 26, 2016 2:39 AM in response to Loner T
    Level 1 (0 points)
    Jan 26, 2016 2:39 AM in response to Loner T

    Thanks for your help. I can assign a letter to the EFI partition, but I'm not sure how to rebuild the BCD using that. /ScanOS returns: "one windows install found on C:". Bootrec /rebuildBCD throws the error about device not found after confirming that I want "C:".

  • by Loner T,Solvedanswer

    Loner T Loner T Jan 26, 2016 6:55 AM in response to cfrz
    Level 7 (24,202 points)
    Safari
    Jan 26, 2016 6:55 AM in response to cfrz

    From https://support.microsoft.com/en-us/kb/927392, you will need to use S: (assigned to EFI) and the appropriate directory within the EFI partition instead of C: shown in the following set of steps. Please see Can't resize Macintosh HD partition as an example of the EFI structure.

     

    /RebuildBcd

    This option scans all disks for installations that are compatible with Windows Vista or Windows 7. Additionally, it lets you select the installations that you want to add to the BCD store. Use this option when you must completely rebuild the BCD store.

     

    Note Use the Bootrec.exe tool to troubleshoot a "Bootmgr Is Missing" error. If rebuilding the BCD store doesn't resolve the startup issue, you can export and delete the BCD store and then run this option again. By doing this, you make sure that the BCD store is completely rebuilt.

     

    To do this, type the following commands at the Windows RE command prompt:

    • bcdedit /export C:\BCD_Backup
    • c:
    • cd boot
    • attrib bcd -s -h -r
    • ren c:\boot\bcd bcd.old
    • bootrec /RebuildBcd

  • by cfrz,

    cfrz cfrz Jan 27, 2016 5:16 AM in response to Loner T
    Level 1 (0 points)
    Jan 27, 2016 5:16 AM in response to Loner T

    It's fixed! First I had to manually rebuilt the BCD as you suggested, and I followed this. Then I had to repair a registry file error (since SFC wasn't working) by copying the backup file as per this. Thanks so much for the help!

  • by Loner T,

    Loner T Loner T Jan 27, 2016 7:09 AM in response to cfrz
    Level 7 (24,202 points)
    Safari
    Jan 27, 2016 7:09 AM in response to cfrz

    Did you create a new EFI partition? If yes, it may cause issues with the Apple EFI because the S: is shared with the Apple EFI on the same partition.

  • by cfrz,

    cfrz cfrz Jan 27, 2016 3:07 PM in response to Loner T
    Level 1 (0 points)
    Jan 27, 2016 3:07 PM in response to Loner T

    Oops, I meant to link this. I only rebuilt the BCD on the S:\Windows\Boot directory of the existing EFI partition. Everything seems to be working fine.

  • by Loner T,

    Loner T Loner T Jan 27, 2016 3:11 PM in response to cfrz
    Level 7 (24,202 points)
    Safari
    Jan 27, 2016 3:11 PM in response to cfrz

    Excellent and thanks for the update.

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