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User profile for user: Mike Floutier
Mike Floutier Author
User level: Level 1
4 points

Window 7 Bootcamp won't start and doesn't appear in boot options despite appearing in Startup Disk

Hi,


I have two partitions, with High Sierra on one and BootCamp Windows 7 SP1 64bit on the other.


All was good (W7 installed and running fine) except that I needed more space on my BootCamp partition. BootCamp Assistant limits me to 40Gb so I was planning to try Partition Wizard from Minitools. This required me to reduce the size of my Mac partition, something which Disk Utility won't allow. As a workaround, I tried creating and additional partition - to provide "unallocated" space for Partition Wizard to use.


Unfortunately this action seemed to mess with some setting (MBR?) and so, despite appearing in "Preferences > Startup Disk" my BootCamp W7 would not start, either from "Startup Disk", OR "Restart > hold Option key..."


This has happened in the past, and I had to delete my BootCamp partition, which is recognised by Disk Utility, and completely reinstall W7, and do all 199 updates and download all my needed software and reload all my (fortunately) backed up data....


However, this take forever.


Any suggestions, since it's obviously all still there, just not accessible, yet....



PS. Frustratingly I can even read my entire BootCamp partition data, down to the last "." in my High Sierra Finder window....

Mac mini, macOS 10.13

Posted on May 10, 2020 1:25 AM

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User profile for user: Loner T
Loner T
User level: Level 9
59,513 points

Posted on May 10, 2020 7:11 PM

Install GPT Fdisk (aka gdisk). The text in parentheses is for informational purpose to describe the action being taken. Gdisk has one-character commands except when entering numbers.



Rebuild MBR to match the GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers. Please see thesample Q&A as an example. These steps can be repeated if you make a mistake before you get to Step 12, otherwise start from Step 1 for these steps. Step 6 has numbers which are typed with a space between the numbers. Please see the sample Q&A before you execute these steps.

  1. Sudo gdisk /dev/rdisk0
  2. P (Print list of parts)
  3. R (Recover)
  4. O (print current Hybrid MBR)
  5. H (chooses Hybrid)
  6. Partitions numbers to be hybridized: 2 3 4
  7. Y (Good for GRUB question)
  8. N (part 2 boot flag)
  9. N (part 3 boot flag)
  10. Y (part 4 boot flag make NTFS bootable partition)
  11. O (print current Hybrid MBR)
  12. W (Write the new MBR)
  13. Y (Yes! write the new MBR)
  14. Reboot


Here is sample Q&A for this section. Please notice the Press Enter/Return.


Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)
Enter an MBR hex code (default AF): Press Enter/Return
Set the bootable flag? (Y/N): N

Creating entry for GPT partition #3 (MBR partition #3)
Enter an MBR hex code (default AB): Press Enter/Return
Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #4)
Enter an MBR hex code (default 07): Press Enter/Return
Set the bootable flag? (Y/N): Y


Test 1 - Does Bootcamp Volume show up in Finder?

Test 2 - Can you see files in Bootcamp Volume?

Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?

Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.

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Question marked as Top-ranking reply
User profile for user: Loner T
Loner T
User level: Level 9
59,513 points

May 10, 2020 7:11 PM in response to Mike Floutier

Install GPT Fdisk (aka gdisk). The text in parentheses is for informational purpose to describe the action being taken. Gdisk has one-character commands except when entering numbers.



Rebuild MBR to match the GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers. Please see thesample Q&A as an example. These steps can be repeated if you make a mistake before you get to Step 12, otherwise start from Step 1 for these steps. Step 6 has numbers which are typed with a space between the numbers. Please see the sample Q&A before you execute these steps.

  1. Sudo gdisk /dev/rdisk0
  2. P (Print list of parts)
  3. R (Recover)
  4. O (print current Hybrid MBR)
  5. H (chooses Hybrid)
  6. Partitions numbers to be hybridized: 2 3 4
  7. Y (Good for GRUB question)
  8. N (part 2 boot flag)
  9. N (part 3 boot flag)
  10. Y (part 4 boot flag make NTFS bootable partition)
  11. O (print current Hybrid MBR)
  12. W (Write the new MBR)
  13. Y (Yes! write the new MBR)
  14. Reboot


Here is sample Q&A for this section. Please notice the Press Enter/Return.


Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)
Enter an MBR hex code (default AF): Press Enter/Return
Set the bootable flag? (Y/N): N

Creating entry for GPT partition #3 (MBR partition #3)
Enter an MBR hex code (default AB): Press Enter/Return
Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #4)
Enter an MBR hex code (default 07): Press Enter/Return
Set the bootable flag? (Y/N): Y


Test 1 - Does Bootcamp Volume show up in Finder?

Test 2 - Can you see files in Bootcamp Volume?

Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?

Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.

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User profile for user: Mike Floutier
Mike Floutier Author
User level: Level 1
4 points

May 10, 2020 11:03 PM in response to Loner T

Hello Loner T, this is Mike F speaking to you from Windows 7 on BootCamp, although it feels like the moon, after this journey.


Thank you sooo much for your help with this, having read a little of Rod's writeup about gdisk I knew it was going to be way beyond my ability to comprehend.


All went smoothly, thanks to your impeccable instructions, all tests successful. W7 started fine from Preferences > Startup. I did try it next from "Alt - start", which showed the W7 partition; first time it started W7 in a sort of lo-res mode with icons re-arranged BUT next time all was back to normal.


I have removed Minitools Partition Wizard, thanks for the tip.


On that subject (and this was the reason I got into this pickle in the first place) can you please give me an idea as to how I could enlarge my BootCamp partition? I followed the usual suggestions but:


  1. When using BootCamp Assistant, it only offers 8Gb or 40Gb and I'm almost out of space on 40Gb.
  2. When trying to reduce the size of my Mac OS partition, that is not offered in Disk Utility.


This was how I got to the Minitools Partition Wizard stage, I do need Windows to successfully use certain video/streaming software otherwise I'd stick to High Sierra.


Anyway thank you, your help is so appreciated!

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User profile for user: Mike Floutier
Mike Floutier Author
User level: Level 1
4 points

May 10, 2020 7:47 AM in response to Loner T

Thanks Loner T:


/dev/disk0 (internal, physical):

  #:            TYPE NAME          SIZE    IDENTIFIER

  0:   GUID_partition_scheme            *500.1 GB  disk0

  1:            EFI EFI           209.7 MB  disk0s1

  2:         Apple_HFS High Sierra       459.2 GB  disk0s2

  3:         Apple_Boot Recovery HD       650.0 MB  disk0s3

  4:    Microsoft Basic Data BOOTCAMP        40.0 GB  disk0s4


Sorry, I couldn't do the other two as I don't know my password. Pretty lame I know but I didn't think I had one, I always just press return when asked for a password.


To check I just tried unlocking StartDisk changes and Return worked as my password??


Is there some special way of entering "Return" in Terminal maybe?


Any ideas?

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User profile for user: Mike Floutier
Mike Floutier Author
User level: Level 1
4 points

May 10, 2020 8:12 AM in response to Mike Floutier

Ok, it obviously didn't like me NOT having a password so I changed my non-password for a real one and it was happy:


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 - 976773167] <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 


-----


gpt show: /dev/disk0: mediasize=500107862016; sectorsize=512; blocks=976773168

gpt show: /dev/disk0: PMBR at sector 0

gpt show: /dev/disk0: Pri GPT at sector 1

gpt show: /dev/disk0: Sec GPT at sector 976773167

   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 896970936   2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

 897380576  1269536   3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

 898650112  78123008   4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

 976773120     15     

 976773135     32     Sec GPT table

 976773167     1     Sec GPT header


Thanks for the tip about Partition Wizard btw!

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User profile for user: Mike Floutier
Mike Floutier Author
User level: Level 1
4 points

May 10, 2020 10:42 AM in response to Loner T

Thanks, it's:


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 50 90 35 |........?....P.5|

00000020 00 00 00 00 80 00 80 00 ff 0f a8 04 00 00 00 00 |................|

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 12 c8 48 3c 01 49 3c 2c |..........H<.I<,|

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 70 0e 16 68 09 00 66 53 66 53 66 |h...hp..h..fSfSf|

00000100 55 16 16 16 68 b8 01 66 61 0e 07 cd 1a 33 c0 bf |U...h..fa....3..|

00000110 28 10 b9 d8 0f fc f3 aa e9 5f 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 a0 f8 01 e8 09 00 |...u...fa.......|

00000170 a0 fb 01 e8 03 00 f4 eb fd b4 01 8b f0 ac 3c 00 |..............<.|

00000180 74 09 b4 0e bb 07 00 cd 10 eb f2 c3 0d 0a 41 20 |t.............A |

00000190 64 69 73 6b 20 72 65 61 64 20 65 72 72 6f 72 20 |disk read error |

000001a0 6f 63 63 75 72 72 65 64 00 0d 0a 42 4f 4f 54 4d |occurred...BOOTM|

000001b0 47 52 20 69 73 20 6d 69 73 73 69 6e 67 00 0d 0a |GR is missing...|

000001c0 42 4f 4f 54 4d 47 52 20 69 73 20 63 6f 6d 70 72 |BOOTMGR is compr|

000001d0 65 73 73 65 64 00 0d 0a 50 72 65 73 73 20 43 74 |essed...Press Ct|

000001e0 72 6c 2b 41 6c 74 2b 44 65 6c 20 74 6f 20 72 65 |rl+Alt+Del to re|

000001f0 73 74 61 72 74 0d 0a 00 8c a9 be d6 00 00 55 aa |start.........U.|

00000200

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Window 7 Bootcamp won't start and doesn't appear in boot options despite appearing in Startup Disk

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