"missing operating system"

Question

Level 1

37 points

"missing operating system"

Hi all, I have, in stages, updated my creaky old early 2009 Mac Pro to work with Catalina 10.5.7. I installed the OS on the same drive as the Boot Camp partition (Windows 7 Home Premium) but that may have been a mistake. I can see the Bootcamp image in disk startup preferences but when I restart with that selected, I get the dreaded "missing operating system" error on a black screen. I've looked around here and elsewhere for how to fix the issue but it looks sort of involved and depends on looking at the partitions to see what the problem is. Here are the common listings I usually see that are used to help solve the problem, from my computer...

from diskutil list disk0:

from sudo fdisk /dev/disk0:

from sudo gpt -r show /dev/disk0:

I have seen the use of a tool (but can't recall what it was right now) that can be used to fix problems with the MBR (if that's the problem here). I'm not too leery of using the terminal to fix it if it can be repaired this way.

There is another thing I can try as well. I have WinClone backups so maybe it's possible for me to create a partition on another drive that only has High Sierra on it and restore BC there. In the meantime I'd appreciate it very much if anyone can show me what to do about fixing the issue with the drive BC is already on. Thank you!

Mac Pro, macOS 10.13

Posted on Jan 18, 2021 2:08 PM

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Answer 1

Loner T

Level 9

59,536 points

Jan 24, 2021 2:01 PM in response to J Harvey

J Harvey wrote:

Thanks for all your help. After trying the fixes that were suggested I got a "BOOTMGR missing" error. I started digging into that issue and came up with a fix in an older thread:

https://neosmart.net/wiki/recovering-windows-bootloader/#Attempt_One_Automated_Repair

" Attempt Two: Manually Repairing the Windows Bootloader" was the one that finally worked for me.

This would have been the next logical step with Bootrec.exe. Glad you found it. Very 😎.

I've noticed you've been quite involved in Windows issues for a long time in Apple discussions. I want to thank you again for not just assisting, but also educating me (and others) about Windows and what to look for when things go wrong.

Glad to see you back in business. Please post back if you run into any further issues.

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Answer 2

Loner T

Level 9

59,536 points

Jan 18, 2021 3:53 PM in response to J Harvey

Your Mac Pro (Early 2009) - Technical Specifications does not officially support Catalina. Identify your Mac Pro model - Apple Support shows the last macOS is El Capitan. If you forced an upgrade, it can cause issues.

Also, you will need /fixMBR and /fixBoot under Bootrec.exe. See https://support.microsoft.com/en-in/help/927392/use-bootrec-exe-in-the-windows-re-to-troubleshoot-startup-issues for reference.

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Answer 3

Loner T

Level 9

59,536 points

Jan 21, 2021 5:20 PM in response to J Harvey

If you reboot the MP and hold Alt/Option with the W7 DVD inserted in the built-in Superdrive, do you see it as an available selection?

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Answer 4

Loner T

Level 9

59,536 points

Jan 22, 2021 6:52 PM in response to J Harvey

Can you connect the Keyboard and Mouse to separate USB rear ports and check?

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Answer 5

Loner T

Level 9

59,536 points

Jan 18, 2021 3:28 PM in response to J Harvey

Can you see Windows files in macOS Finder?

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Answer 6

Loner T

Level 9

59,536 points

Jan 19, 2021 7:56 AM in response to J Harvey

Do you have W7 DVD that you can boot from? Bootrec.exe is included on that DVD. We can then point to the specific W7 disk/partition and try to correct the MBR.

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Answer 7

Loner T

Level 9

59,536 points

Jan 23, 2021 4:40 PM in response to J Harvey

We need to boot from the Install Disk and choose the Repair option. If you can see your Windows files, we need Bootrec.exe to run /fixMBR and /fixBoot.

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Answer 8

J Harvey Author

Level 1

37 points

Jan 24, 2021 12:58 PM in response to Loner T

Thanks for all your help. After trying the fixes that were suggested I got a "BOOTMGR missing" error. I started digging into that issue and came up with a fix in an older thread:

https://neosmart.net/wiki/recovering-windows-bootloader/#Attempt_One_Automated_Repair

" Attempt Two: Manually Repairing the Windows Bootloader" was the one that finally worked for me.

I've noticed you've been quite involved in Windows issues for a long time in Apple discussions. I want to thank you again for not just assisting, but also educating me (and others) about Windows and what to look for when things go wrong.

Reply

Answer 9

J Harvey Author

Level 1

37 points

Jan 21, 2021 4:59 PM in response to Loner T

Just an update. I found my Win7 installation disk and the recovery disk. I can't seem to boot from either one. My Superdrive tells me they're blank disks when I insert them. I have tried booting from my second optical drive but nothing happens more than a black screen with a message I can't recall right now. I'm also trying some other approaches that may work but they will take a bit of time.

I am curious though as how to boot from either of these disks for repair work.

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Answer 10

J Harvey Author

Level 1

37 points

Jan 22, 2021 2:08 PM in response to Loner T

Yes I see it as an available selection. After I try to boot from it I get a black screen and a prompt to hit any key to boot from CD or DVD and it doesn't respond to any key presses. I have a USB mouse and keyboard plugged in.

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Answer 11

J Harvey Author

Level 1

37 points

Jan 23, 2021 2:11 PM in response to Loner T

Yes. I've gotten both the installation disk and recovery disk to boot after unplugging the USB mouse and making sure to hit a key as soon as the disk loaded. First 2 photos are from the recovery disk and the 3rd from the install disk. Of course the same recovery windows as in the recovery disk are shown in the installation disk when you click on "repair your computer".

Obviously the bootcamp partition was found, so where do I go from here? I was going to let the Windows software do the repair but I wasn't sure if that was the right thing to do. Thank you for helping!

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Answer 12

J Harvey Author

Level 1

37 points

Jan 24, 2021 5:13 AM in response to Loner T

Well for some reason that dialog box went away when booting from the Recovery Disk but I was able to get to a CMD prompt through "safe mode with command prompt" and I could run bootrec.exe as shown. Would this work for what needs to be done?

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