You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Mavericks messed up the Windows partition

Hello guys, when I was running Mountain Lion I needed more space on my Windows 8.1 partition so I shrank the Mac partition using Disk Utility then used a third party software on windows to expand the Bootcamp partition. And when I installed Mavericks yesterday it seems like the partitions got messed up and I ended up with Windows not being detected at all (no signs of it except "disk0s4" on Disk Utility) then I found a solution suggested by Christopher Murphy suggesting a change of the volume's id to something like 07 then setting it as active (*) and that got Windows back on the boot selection menu (when holding alt key) but still no signs of it on the finder. However, now I'm faced with another problem : when I start Windows, it turns into a black screen and says "Operating system not found"

User uploaded file

I desperately tried using a USB Installation drive of Windows 8.1 to repair the problem with the "Startup repair" however it fails. When tried to "refresh the installation" this happens:

User uploaded file

which I think means that the recovery tool can't read the Windows partition...

Some users suggested showing results for both of these commands so here are they:

iMac:~ wassgha$ sudo gpt -r -vv show disk0
Password:
gpt show: disk0: mediasize=500107862016; sectorsize=512; blocks=976773168
gpt show: disk0: Suspicious MBR at sector 0
gpt show: disk0: Pri GPT at sector 1
gpt show: disk0: Sec GPT at sector 976773167
      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  482321096      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  482730736    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  484000272  154398192         
  638398464  338374656      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  976773120         15         
  976773135         32         Sec GPT table
  976773167          1         Sec GPT header
iMac:~ wassgha$ sudo fdisk /dev/disk0
Disk: /dev/disk0 geometry: 60801/255/63 [976773168 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
 2: AF 1023 254  63 - 1023 254  63 [    409640 -  482321096] HFS+        
 3: AB 1023 254  63 - 1023 254  63 [ 482730736 -    1269536] Darwin Boot 
*4: 07 1023 254  63 - 1023 254  63 [ 638398464 -  338374656] HPFS/QNX/AUX

and looking at the results, we can clearly see a gap between the "Darwin Boot" and the Windows partition (409640 + 482321096 does equal 482730736 but 482730736 + 1269536 which should be 484000272 and that's where the windows partition should start, is shown as 638398464 so there's a gap of 154398192 bytes that should contain the boot manager and a lot of necessary Windows files...)

Can someone please help me? I'd do anything to get my Windows partition back without loss of files... The files are important to me and I was stupid not to back up...

iMac, OS X Mavericks (10.9.4)

Posted on Jul 26, 2014 12:27 PM

Reply
18 replies

Jul 28, 2014 2:38 PM in response to Loner T

iMac:~ wassgha$ sudo dd if=/dev/rdisk0s4 count=1 2>/dev/null | hexdump -C
Password:
00000000  50 63 6d 48 01 00 00 00  00 00 00 00 c3 b3 d6 28  |PcmH...........(|
00000010  74 f1 49 f8 15 00 00 00  94 00 00 00 0e 00 00 00  |t.I.............|
00000020  54 00 00 00 00 00 00 00  00 00 00 00 02 00 00 00  |T...............|
00000030  8c 00 00 00 00 00 00 00  00 00 00 00 04 00 00 00  |................|
00000040  ff ff ff ff ff 1b 35 28  25 d5 55 41 ac b0 6e 7c  |......5(%.UA..n||
00000050  64 c7 25 d8 11 00 00 00  07 00 00 00 09 00 00 00  |d.%.............|
00000060  0a 00 00 00 08 00 00 00  13 00 00 00 0f 00 00 00  |................|
00000070  0b 00 00 00 12 00 00 00  0c 00 00 00 10 00 00 00  |................|
00000080  0d 00 00 00 14 00 00 00  0e 00 00 00 06 00 00 00  |................|
00000090  05 00 00 00 1c 00 00 01  74 01 00 00 1c 00 00 01  |........t.......|
000000a0  d8 02 00 00 1c 00 00 06  44 01 00 00 08 00 00 01  |........D.......|
000000b0  60 01 00 00 14 00 00 09  38 02 00 00 40 00 00 04  |`.......8...@...|
000000c0  4c 02 00 00 40 00 00 04  90 01 00 00 01 00 00 02  |L...@...........|
000000d0  20 02 00 00 26 00 00 02  f8 01 00 00 18 00 00 02  | ...&...........|
000000e0  d0 01 00 00 04 00 00 02  68 01 00 00 0e 00 00 02  |........h.......|
000000f0  e8 01 00 00 15 00 00 02  8c 02 00 00 0c 00 00 02  |................|
00000100  a4 02 00 00 0e 00 00 02  b0 02 00 00 0e 00 00 02  |................|
00000110  f4 02 00 00 05 00 00 02  c0 02 00 00 12 00 00 02  |................|
00000120  24 02 00 00 10 00 00 02  c8 02 00 00 07 00 00 02  |$...............|
00000130  3c 01 00 00 06 00 00 02  6c 01 00 00 56 65 72 73  |<.......l...Vers|
00000140  69 6f 6e 00 01 02 00 00  f2 ca 84 f0 02 7d ff ff  |ion..........}..|
00000150  00 00 00 00 01 00 00 00  00 00 00 00 01 00 00 00  |................|
00000160  02 00 00 00 01 00 00 00  4e 61 6d 65 4e 6f 6e 53  |........NameNonS|
00000170  78 53 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |xS..............|
00000180  00 00 00 00 ff ff ff ff  ff ff ff ff 00 00 00 00  |................|
00000190  05 00 00 00 ff ff ff ff  03 00 00 00 04 00 00 00  |................|
000001a0  ff ff ff ff 05 00 00 00  0d 00 00 00 ff ff ff ff  |................|
000001b0  07 00 00 00 08 00 00 00  ff ff ff ff 09 00 00 00  |................|
000001c0  0a 00 00 00 ff ff ff ff  0b 00 00 00 0c 00 00 00  |................|
000001d0  46 69 6c 65 4d 61 6e 61  67 65 72 5c 41 73 73 65  |FileManager\Asse|
000001e0  74 73 5c 46 6f 6e 74 73  50 75 62 6c 69 63 4b 65  |ts\FontsPublicKe|
000001f0  79 54 6f 6b 65 6e 00 00  4d 69 63 72 6f 73 6f 66  |yToken..Microsof|
00000200
iMac:~ wassgha$

Here is it 🙂

Jul 28, 2014 2:51 PM in response to wassgha

Your NTFS file system is corrupted. Do you have a DVD for your Windows installation. Since the DVD is read-only it is less likely to cause file system confusion during recovery. A USB can confuse Windows repair, because it is a writable system.


If you have a DVD (or you can burn it from your USB on the OSX side) and a DVD drive (internal or external), connect it to the Mac. Power cycle the Mac, and hold the ALT key select the hard disk which says Windows (do not select the DVD). The CSM-BIOS layer when windows boots up will try to start from the DVD, if the hard disc partition is not bootable. It should say 'Press any key to boot from CD/DVD'. Once it boots from the CD/DVD, it should have bootrec.exe on the DVD, which can be used to fix the MBR. Please see http://support.microsoft.com/kb/927392 which shows what options can be used with bootrec.exe. You may need /scanos, /fixmbr and /fixboot qualifiers based on what you see.


Refresh your PC is unlikely to work. It looks like it needs Startup Repair.

Jul 28, 2014 3:15 PM in response to Loner T

I tried using a Windows 7 installation DVD, it booted up after choosing Windows from the boot menu but the repair tool doesn't detect any windows installations nor does bootrec.exe ... Maybe that's because Windows 8 isn't compatible with the Windows 7 recovery software? I'll see if I can get my hands on a Windws 8 installation disk tomorrow if that's the problem...

Mavericks messed up the Windows partition

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.