El Capitan and Windows 7 Legacy Dual Boot Broke

[ellissitzky]

[Solved partially] El Capitan and Windows 7 Legacy Dual Boot Broke

Update: Despite 99% of the research I did suggesting the cause was a corrupt boot sector/MBR, the issue appears to be isolated to my Clover boot loader because upon attempting to boot with a Chimera USB Win 7 booted perfectly fine.

Background: I have a machine that was previously dual booting legacy El Capitan and Windows 7 off of the same drive on a non-UEFI board.

Issue: When I try to boot the Win 7 entry through Clover I get a "Disk Read Error".

Possible causes: The El Capitan install is a recent fresh replacement of the Mavericks install. I will try to retrace my steps that may have caused this but the troubleshooting took place about a month ago and was a lengthy process.

1. If I recall correctly, upon first installing the new El Capitan, Clover was not loading off the drive and instead I was getting a Windows boot menu. To remedy this I think I had to switch the Boot0 to AF or SS. After that I can say with certainty the system was booting both OSs fine.

2. Then there was an issue at some point where the EFI was improperly formatted as HFSJ so I had to set it back to FAT32 and I think at this point the dual booting was still in tact.

3. At a later point I tried to format the EFI again in order to troubleshoot another issue but accidentally improperly formatted it. In order to fix that I found a post on Stack Exchange that detailed out to swap the EFI out from starting to ending byte with the EFI from my boot USB.

4. I reset my BIOS to factory defaults.

These are the possible things that may have caused this issue but I'm not sure.

Questions:

• Is my boot partition damaged?
• Is there BIOS or Clover setting causing this issue?
• Is there a possible way to examine the boot partition or see a detailed log that may hint at what is causing the "Disk Read Error"?
• Is there any possible way I can repair this with out having to install both OSs from scratch?

 

[Going Bald]

—Also at another point I damaged my boot sector and I don't remember how but I did a really in-depth tutorial on how to grab the boot sector from my bootable USB and transplant it in the OS X entry, which shouldn't have affected the Windows entry.

And this is where you lost your Windows boot information. Windows and OS X share the boot sector.

Suggest you re-install from scratch both OS X and Windows, making sure to select Clover Legacy boot mode when you create your UniBeast USB and when you run MultiBeast post install select the Quick Start->Legacy Boot

 

[ellissitzky]

Hey! Thanks a ton for the response.

Say it ain't so!

I'm trying to remember exactly what happened in that last issue. I remember now that I went to wipe the EFI partition and accidentally formatted it to the wrong partition or something. I think I found a post on Stack Exchange that had me swap the EFI partition down to the exact bytes in Terminal with EFI partition on my boot USB. Would that have messed up the Win MBR?

I'd like to avoid fresh installing El Capitan at all costs because my install is set up perfect now after a lot of troubleshooting. I don't mind fresh installing Windows as much. If I took a different route and shelled out for another drive to install Windows on, something I was already considering, would it be a hassle reclaiming the rest of that drive for that OS X install?

 

[Going Bald]

Hey! Thanks a ton for the response.

Say it ain't so!

I'm trying to remember exactly what happened in that last issue. I remember now that I went to wipe the EFI partition and accidentally formatted it to the wrong partition or something. I think I found a post on Stack Exchange that had me swap the EFI partition down to the exact bytes in Terminal with EFI partition on my boot USB. Would that have messed up the Win MBR?

I'd like to avoid fresh installing El Capitan at all costs because my install is set up perfect now after a lot of troubleshooting. I don't mind fresh installing Windows as much. If I took a different route and shelled out for another drive to install Windows on, something I was already considering, would it be a hassle reclaiming the rest of that drive for that OS X install?

If you have the budget for an additional drive for Windows that is the way I would go. I always recommend separate drives. Reclaiming it for OS X is easy with the old disk utility. Not sure how you would do it with the one in El Cap (sucks bigtime IMHO- horrible interface).

 

[ellissitzky]

Thanks for the prompt response!

• Is there a guide or definitive post about legacy dual booting so I can educate myself a little more?
• Is there an application I can run to examine the boot partition to see what exactly is wrong with it?
• Is it possible to see at what point the "Disk read error" is occurring or a more detailed error log?
• If I can't reclaim it with the new diskutil would it be safe to throw an older OS X with the old diskutil on a USB and boot that to reclaim?

FYI this is the post I used to fix the previous issue I had that may be the cause of this current one: http://apple.stackexchange.com/questions/57597/how-to-fix-broken-efi-partition

 

[Going Bald]

Thanks for the prompt response!

• Is there a guide or definitive post about legacy dual booting so I can educate myself a little more?
• Is there an application I can run to examine the boot partition to see what exactly is wrong with it?
• Is it possible to see at what point the "Disk read error" is occurring or a more detailed error log?
• If I can't reclaim it with the new diskutil would it be safe to throw an older OS X with the old diskutil on a USB and boot that to reclaim?

FYI this is the post I used to fix the previous issue I had that may be the cause of this current one: http://apple.stackexchange.com/questions/57597/how-to-fix-broken-efi-partition

http://www.tonymacx86.com/multi-booting/96000-guide-dual-booting-mountain-lion-windows-8-a.html

If the new DU will not reclaim the Windows partition, clone your install to a USB drive, reformat the main drive and then clone the USB back to the main drive.

 

[ellissitzky]

Thanks!

Can you recommend a cloner? Can I just use my Time Machine backup?

Do I clone the entire drive and just omit the Win partition? Will that allow me to retain my GPT or does the cloner create a new one?

 

[Going Bald]

Thanks!

Can you recommend a cloner? Can I just use my Time Machine backup?

Do I clone the entire drive and just omit the Win partition? Will that allow me to retain my GPT or does the cloner create a new one?

Format the drive same as the OS X drive, use Carbon Copy Cloner (CCC) or SuperDuper to clone your drive. Run MultiBeast and select same items you selected for original install, pointed at the clone drive to make it bootable. Then you can reformat then old drive and clone your clone back to your old drive.

 

[ellissitzky]

Is this a joke?

I spent 14 straight hours yesterday, no exaggeration, trying to research and fix this issue and not once was there a single hint to try another boot loader.

Well. I got the hunch maybe it was Clover and I decided to make a Chimera USB. And guess what? Windows booted.

I basically just ordered another SSD for no reason.

It's prompting me to repair the start up files because it didn't boot before. That issue is unrelated and will break my GPT if I repair, right?

Why is Chimera working and Clover not?

Since it at some point Win DID boot using Clover, what's the safest way I can wipe out the EFI in an attempt to clear any rogue setting or file that may be stopping Win from booting? Or is that already ruled out because attempting to boot with my Clover boot USB just brings the Win boot to a blinking cursor?

 

[ellissitzky]

.........

Hitting exit in Clover boots Windows...

72 hours later.