Windows – Lost Windows Bootcamp boot entry after resizing the partition

bootbootcampdual-bootpartitionwindows

I have a 2011 iMac that I had used Bootcamp utility to install Windows 7 on. I got overzealous and tried to triple boot Windows, Mac and Linux on the iMac. I no longer need Linux on this iMac but the process corrupted my boot table and now I can't boot into Windows. If I press and hold 'alt/option' key after it reboots it doesn't show me the Windows bootcamp boot entry — just Mac and Recovery drive.

However, in the file system, I still see all the files for Windows intact. So the file structure is still there, just the boot table entry is messed up somehow. I tried to 'repair' it but Bootcamp utility no longer gives me the optin of making a bootable Windows thumb drive using the Windows ISO that I have. It just asks to download some support software for Windows and that's it.

If this was Linux, I'd use something like 'boot repair' ISO or 'update-grub' to update the boot table but how do I repair the boot entry in Mac?

I have the Windows ISO available and I'm comfortable with command-line.

UPDATE: Details about the system

users-iMac:~ user$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            598.5 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data BOOTCAMP                400.8 GB   disk0s4

/dev/disk1 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *16.0 GB    disk1
   1:                 DOS_FAT_32 FAT32                   16.0 GB    disk1s1

/dev/disk2 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:        CD_partition_scheme Audio CD               *410.5 MB   disk2

GPT:

users-iMac:~ user$ sudo gpt -r show /dev/disk0
Password:
gpt show: /dev/disk0: Suspicious MBR at sector 0
       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  1168862256      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  1169271896     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  1170541432   782721552      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  1953262984      262151         
  1953525135          32         Sec GPT table
  1953525167           1         Sec GPT header

Fdisk:

users-iMac:~ user$ sudo fdisk /dev/disk0
Disk: /dev/disk0    geometry: 121601/255/63 [1953525168 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 - 1168862256] HFS+        
 3: AB 1023 254  63 - 1023 254  63 [1169271896 -    1269536] Darwin Boot 
 4: 0B 1023 254  63 - 1023 254  63 [1170541432 -  782721552] Win95 FAT-32

The optical drive on my system works. I was wondering if I could create a bootable thumb drive though. Bootcamp does not give me this option in the 2011 iMac but I was hoping to the edit the 'info.plist' in Bootcamp's contents folder to add my iMac model in there so that Bootcamp gives me the option of booting from thumb drive. This "patch" is described here: Bootcamp – No ISO Option

But is there any other simpler way to create a bootable thumb drive to install Windows on a Mac?

Best Answer

There are ways to create a bootable Windows installer thumb drive. The problem is you can not use this thumb drive with your computer. The software that searches the USB ports for bootable flash drives is part of the the firmware located on the main logic board. This firmware is not part of the OS X (macOS) operating system. Even though the firmware for the 2011 iMac can boot OS X (macOS) and certain Linux versions from a thumb drive, the Windows 7 installer can not be booted this way. The best option is to use original internal optical (DVD) drive. I would recommend a RW DVD which takes longer to burn, but is reusable.

If the Windows partition is intact, there are three main reasons you can not boot Windows. These reasons are listed below and apply to Mac computers which are booting Windows using the BIOS method.

The values in the partition tables are wrong. There are two partition tables. The first is the legacy Master Boot Record (MBR) table and the second is the newer GUID Partition Table (GPT). The bootable Windows partition must exist in both of these tables. The MBR table is stored at the beginning of the drive, followed by the GPT header and array of partition entries. There is also a backup copy of this GPT header and array at the end of the drive.
The MBR does not contain the correct code needed to boot Windows. The BIOS boot methods reads at least the first 512 bytes stored on the boot drive into memory and execute the code contained in this 512 bytes. These bytes are referred to as the MBR which also contains the MBR table. This code reads the MBR table and determines which partition to boot Window from. If this code is missing or incorrect, Windows will not boot.
Finally, the Windows Boot Configuration Data (BCD) is missing or contains the wrong data. If a change is made to your computer or if the Windows partition is moved regardless if within the same or to different computer, the BCD may need to be corrected or simply recreated. As far as I know, this can only be done (without using a third party tool) by booting from proper Windows installation media. In your case this would be a DVD containing the Windows installation software.

The output from the fdisk command shows the MBR table contains some incorrect values. This output should have appeared as shown below.

users-iMac:~ user$ sudo fdisk /dev/disk0
Disk: /dev/disk0    geometry: 121601/255/63 [1953525168 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 - 1168862256] HFS+        
 3: AB 1023 254  63 - 1023 254  63 [1169271896 -    1269536] Darwin Boot 
*4: 07 1023 254  63 - 1023 254  63 [1170541432 -  782721552] HPFS/QNX/AUX

Basically, your forth partition (where Windows resides) has the wrong id (partition type) and is not flaged as active (bootable).

The MBR table can be corrected by using the fdisk command. This command is interactive. An example the the necessary command line entries is shown below.

users-iMac:~ user$ sudo fdisk -e /dev/disk0
Password:
fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory
Enter 'help' for information
fdisk: 1> e 4
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 4: 0B 1023 254  63 - 1023 254  63 [1170541432 -  782721552] Win95 FAT-32
Partition id ('0' to disable)  [0 - FF]: [B] (? for help) 7
Do you wish to edit in CHS mode? [n] 
Partition offset [0 - 1953525168]: [1170541432] 
Partition size [1 - 782721552]: [782721552] 
fdisk:*1> f 4
Partition 4 marked active.
fdisk:*1> q
Writing current MBR to disk.
Device could not be accessed exclusively.
A reboot will be needed for changes to take effect. OK? [n] y
users-iMac:~ user$

NOTE: For you can just hit a return instead of entering values for the entries shown below. This will instruct fdisk to use the default values. This is what I did in the above example.

Do you wish to edit in CHS mode? [n] 
Partition offset [0 - 1953525168]: [1170541432] 
Partition size [1 - 782721552]: [782721552]

If you have System Integrity Protect (SIP) enabled, you may have to temporarily disable SIP in order to execute the fdisk command.

If after correcting the MBR table your Mac will not boot Windows, we can try to determine if the other causes listed above may also be at fault.

Related Solutions

MacOS – Mac Mini 2010: DualBoot (BootCamp) OSX Mavericks + Windows 8.1

I tried to use virtualbox by enabling it permissions access to my whole drive. This also did not work.

The only available solution, after extensively scanning the web, is to install with the native dvd drive.

However, I am surprised that the community has not defined a better solution. One where one can dual boot windows/ or, bootcamp windows in a macbook 2010 (for example) where the optical drive has been replaced by a second hard drive [without removing the second drive and reinstalling the optical drive]. I am also not satisfied with the cloning a drive option as this too requires removing drives and reinstalling and gaining access to a second mac.

I think that ubuntu (http://www.askubuntu.com/) may be able to define a solution using unix code to fix the problem once and for all!

I think I messed up the Fusion Drive on the 1TB iMac (with BootCamp)

Theoretically everything is fine with your Fusion Drive. Fusion Drives look like this. Disk0 is your SSD with 121 GB and disk1 is your HDD with ~1 TB (~1.121 TB summed up).

The larger parts of your SSD (disk0s2) and your HDD (disk1s2) are pooled to a CoreStorage LVG (Fusion Drive: disk3) with a size of 967.8 GB. The rest is reserved for EFIs, a Recovery HD (alltogether ~1.3 GB) and your old Windows partition - now probably free space (~152 GB).

The logical volume 'Macintosh HD' (967.8 GB) spans disk0s2 and disk1s2. This is the first 'Macintosh HD' in picture 1. The volume 'Macintosh HD' - it's the one visible on the desktop - should ideally also have about 967.8 GB. This is the second 'Macintosh HD' in picture 1.
In fact it has only 852.67 GB (see picture 3).

In the second picture the logical volume 'Macintosh HD' is the first listed in black, the volume 'Macintosh HD' is the second listed in black, the other two 'Macintosh HD's listed in grey are the parts of your SSD and HDD dedicated to the logical volume 'Macintosh HD'.

In my opinion something went wrong after deleting various partitions with the Bootcamp Assistant/Disk Utility or in Windows.

Preparation:

Detach any external drive (especially your external Time Machine backup drive)
Restart to Internet Recovery Mode by pressing alt cmd R at startup.
The prerequisites are the latest firmware update installed, either ethernet or WLAN (WPA/WPA2) and a router with DHCP activated.
On a 50 Mbps-line it takes about 4 min (presenting a small animated globe) to boot into a recovery netboot image which usually is loaded from an apple/akamai server.

I recommend ethernet because it's more reliable. If you are restricted to WIFI and the boot process fails, just restart your Mac until you succeed booting.

Alternatively you may start from a bootable installer thumb drive (preferably Mavericks or Yosemite) or a thumb drive containing a full system (preferably Mavericks or Yosemite).

Now you may either repair CoreStorage or rebuild your Fusion Drive:

'Repair CoreStorage' (not recommended):

First i would try to check the volume 'Macintosh HD' with Disk Utility. If the volume is corrupted consider a reinstall of Mac OS X.
If the volume is ok quit Disk Utility
Open Terminal and enter diskutil unmountDisk /dev/LVIdentifier and both diskutil unmountDisk /dev/DiskContainingApple_CoreStorageIdentifier
In your case: first diskutil unmountDisk /dev/disk3 then diskutil unmountDisk /dev/disk0 and diskutil unmountDisk /dev/disk1
remove the EFI NO NAME partition with gpt remove -i IndexNumberOfEFINoName DiskIdentifier:
gpt remove -i 4 disk1
Remount the CoreStorage disks and then the Logical Volume:
In your case: first diskutil mountDisk /dev/disk0 and diskutil mountDisk /dev/disk1 and then diskutil mount /dev/disk3.

enter gpt -r -vvv show /dev/diskIdentfierOfApple_CoreStorage to get infos of your HDD CoreStorage disk.
In your case: gpt -r -vvv show /dev/disk1
It should look like this:

-bash-3.2# gpt -r -vvv show /dev/disk1
gpt show: /dev/disk1: mediasize=1000204886016; sectorsize=512;         blocks=1953525168
gpt show: /dev/disk1: PMBR at sector 0
gpt show: /dev/disk1: Pri GPT at sector 1
gpt show: /dev/disk1: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=40, size=409600
gpt show: /dev/disk1: GPT partition: type=53746F72-6167-11AA-AA11-00306543ECAC, start=409640, size=1671210848
gpt show: /dev/disk1: GPT partition: type=426F6F74-0000-11AA-AA11-00306543ECAC, start=1671620488, size=1269760
gpt show: /dev/disk1: Sec GPT at sector 1953525167                               
     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    1671210848      2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC
1671620488       1269760      3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
1672890248     280634887
1953525135            32        Sec GPT table
1953525167             1        Sec GPT header

The free space on your HDD has 280634887 blocks. Please calculate the biggest block number dividable through 8. That's 280634880 blocks (á 512 bytes) which equals 143685058560 B or ~143.7 GB. Add the size of your HDD CoreStorage Physical Volume (852666400768 B) The result is 143685058560 B + 852666400768 B = 996351459328 B
Resize your HDD CoreStorage physical volume with diskutil cs resizeDisk HDDPVUUID newsize
In your case: diskutil cs resizeDisk 93892BE8-2B7F-4ABD-A4C3-984495DCD98D 996351459328b
Calculate the maximal size of your CoreStorage Logical Volume in diskutil cs list: (size disk0s2) + (size disk1s2) In your case that's 120988852224 B + 996351459328 B = 1117340311552 B. That should be the size of your refreshed Logical Volume Group.
Resize your Logical Volume with diskutil cs resizeVolume LVUUID LVGSize-128 MB In your case that's diskutil cs resizeVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0 1117212311552b. If you get an error (There is not enough free space...) choose a smaller size like 1117148311552b.
Quit Terminal and open Disk Utility.
Check your expanded CoreStorage Volume for errors.
Quit Disk Utility, choose your CS volume as startup disk and restart your Mac

'Rebuild Fusion Drive' (recommended if you have a Time Machine backup)

Booted to Internet Recovery Mode open Utilities → Terminal in the menubar and enter:
diskutil cs list to get the CoreStorage listing.
Copy the Logical Volume UUID, it's the fifth listed.
Now delete the Logical Volume with diskutil cs deleteVolume LVUUID.
In your case: diskutil cs deleteVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0.
Copy the Logical Volume Group UUID, it's the first listed in the listing of diskutil cs list.
Then delete the Logical Volume Group with diskutil cs delete LVGUUID.
In your case: diskutil cs delete 1EFE58BC-3613-44C4-86EE-D816F3B66E3E
Enter exit and quit 'Terminal'
Open 'Disk Utility'. Enter 'Ignore' if you are asked to fix the drives.
Choose your SSD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~121 GB

Example:
Choose your HDD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~1 TB

Example:
Quit Disk Utility and open Terminal
Enter diskutil list

Example (your disk identifiers and sizes are different of course: Your volume SSD probably has the Identifier disk0s2 and the size 121 GB and your volume HDD probably has the Identifier disk1s2 and the size 1.0 TB):
Enter diskutil cs create "Name" IdentifierSSD IdentifierHDD
In your case probably diskutil cs create "Macintosh HD" disk0s2 disk1s2.

Copy the resulting LVGUUID

Example:
Enter diskutil cs CreateVolume LVGUUID jhfs+ "Macintosh HD" 100%.

Example:
Enter diskutil cs list
Check the size of your Logical Volume. It should have the size ~1.121 TB

Example:
Quit Terminal
Open 'Disk Utility' and check your newly created volume for errors
Quit 'Disk Utility'
Attach your external Time Machine backup drive or check this answer if you use NAS or another network share.
Open 'Restore from Time Machine Backup'
Choose the appropriate Time Machine backup and restore your system
Reboot to your restored system.
Unmount and detach your Time Machine backup drive
Open 'Terminal' and enter 'diskutil list'
Check if your 'Recovery HD' is listed.
If your 'Recovery HD' is missing, usually reinstalling your current system with the latest available system installer (e.g. 'Install OS X Mavericks (10.9.5)' if Mavericks is currently installed) will recreate it without loosing any data. AFAIK Recovery Partition Creator 3.8 will NOT create a Recovery HD on CoreStorage volumes.
After reinstalling the system with the latest available system installer open App Store and install the latest security fixes.

Best Answer

Related Solutions

MacOS – Mac Mini 2010: DualBoot (BootCamp) OSX Mavericks + Windows 8.1

I think I messed up the Fusion Drive on the 1TB iMac (with BootCamp)

Related Question