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Windows 10 Bootcamp dual boot problem after El Capitan upgrade

Hi guys,

I have an Early 2013 Retina Macbook Pro (2,6 GHz Interl Core i5, (GB DDR3 RAM, 256 GB SSD) computer.

I used OS X Mavericks with Windows 10 Bootcamp and it worked perfectly until I upgraded to OS X El Capitan (I skipped Yosemite).

Now in the boot menu I can see the Windows partition but if I start that I see "Missing operation system" message.

I tried some of the previous discussions:

https://discussions.apple.com/thread/7254934?start=0&tstart=0

https://discussions.apple.com/thread/7200751

http://nerdr.com/bootcamp-partition-lost-repairing-mac-partitions/


but none of them made any result.

I guess I should do some magic with gdisk and the section numbers but I'm not enough by myself to do that, so could you please help me? I can post any result of the gdisk commands to make this work.


Thanks!

Posted on Oct 7, 2015 1:34 PM

Reply
63 replies

Oct 8, 2015 11:03 AM in response to profendre

In step 8 of the first set of Gdisk steps, you need to use the + sign before the size value.



You need to use the following steps. If you see any error messages during the following steps, please stop and post back here with the error message. The following steps have values from your Testdisk output (and you can verify) in Steps 7 and 8. Please notice the'+' sign in step 8 (this is called offset notation). The text in parentheses is for informational purpose to describe the action being taken. Gdisk has one-character commands except when entering numbers.


Rebuild GPT4 using start/end offsets


  1. Sudo gdisk /dev/rdisk0
  2. P (print the full list of parts)
  3. D (delete)
  4. 4 (part 4)
  5. N (new part)
  6. 4 (part 4)
  7. 236054528 ( - Start offset in sectors or the start point for Bootcamp part)
  8. +254179321 ( - Size offset, as opposed to End offset)
  9. 0700 (Windows part type)
  10. P (print list of all parts just to see what changes will be made)
  11. W (Write the new GPT)
  12. Y (Yes! really write the new GPT)

This will delete and re-write the GPT partition info for /dev/disk0s4.

Rebuild MBR to match the new 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.

Oct 8, 2015 11:27 AM in response to Loner T

First of all thanks for your help and your patience.

I did it again correctly as you said.

Test 1-2-3-4 is all OK, but when I restart in Windows, it says that winload.exe not found or corrupted.

I'm trying to solve that with a windows installation pendrive but still no success.

Anyway I still can see that little empty space before my bootcamp partition. Any idea? Am I still missing something or doing something wrong with your steps?

Oct 9, 2015 2:57 AM in response to Loner T

I created the installer with Boot Camp Assistant, but when I choosed Startup Repair but it said that it was unsuccessful (btw it's better then previously because it offers to choose operation system and I can choose Windows 10). It says that I can see the log in '\System32\Logfiles\Srt\SrtTrail.txt' but I could not find that because in Logfiles there's no Srt folder. Any idea?

Windows 10 Bootcamp dual boot problem after El Capitan upgrade

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