Startup Manager broken

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JeffBB1991 Author

Level 1

8 points

Startup Manager broken

I've installed Windows using Bootcamp utility.

I created a partition on the SSD and installed Windows on it.

after a while I started to run out of space on the Windows partition, but no way to extend that Windows partition. so i created a second partition and formated that partition also as NTFS

eerything worked fine. when starting up the macbook pro I hold down the option key where I can select to boot to Windows or Mac OS.

then I used a program while running Windows to migrate the two partitions together.

I realy tought to be sure it had nothing to to with the Macintosh HD partition.

but when restarting my machine I was not able to boot to Mac anymore.

MacBook Pro 15", macOS 10.15

Posted on Feb 7, 2020 11:18 AM

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Answer 1

Top-ranking reply

BDAqua

Level 10

245,189 points

Feb 7, 2020 11:45 AM in response to JeffBB1991

You may have to erase the drive & start over, does CMD+r work on atartup?

Do you have a Time Machine backup to Restore to/from?

https://support.apple.com/guide/mac-help/revert-to-a-previous-macos-version-mh15216/mac

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Answer 2

JeffBB1991 Author

Level 1

8 points

Feb 7, 2020 12:01 PM in response to BDAqua

Thanks for responding.

I know I have the oppertunity to erase and startover again, but I'm almost sure the OS is still there.

only the so called MBR (at least in Windows) is damaged.

I think it's called "GPT" on Mac OS

GPT stores partitioning and boot data in multiple copies across the disk which makes it easier to recover data in case it is overwritten or corrupted. MBR on the other hand, stores this data in one place which makes it impossible to retrieve data once it is corrupted. GPT also has the ability to store cyclical redundancy values which check whether data is intact, in case data is corrupted, GPT identifies the problem and makes attempts to recover data from the disk’s other locations. MBR does not have that capability of knowing whether data has been corrupted, the only indication is when booting process fails or when drives partitions disappear.

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Answer 3

JeffBB1991 Author

Level 1

8 points

Feb 7, 2020 9:19 PM in response to BDAqua

at this moment I have deleted the partition where Bootcamp (Windows) was installed and installed a second copy of Mac OS

I've noticed that the partition map is damaged it looks like this in diskutil

where Windows Recovery "disk0s2" (don't know how it's gotten this name Windows Recovery.

but i'm almost sure my data from my previous installed version of Macintosh is still there.

how do i get back in there?

(maybe just to copy my files)

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Answer 4

JeffBB1991 Author

Level 1

8 points

Feb 7, 2020 12:03 PM in response to JeffBB1991

Maybe someone knows how to modify the MBR or GPT to access Mac OS again.

Windows is not important to me, but Mac OS is.

or maybe someone knows how to access my files true a bootable mac OS - USB or something.

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Answer 5

HWTech

Level 9

60,380 points

Feb 7, 2020 9:51 PM in response to JeffBB1991

Use Disk Utility First Aid on the physical drive, then on the container and volume. If Disk Utility cannot repair the drive and volume, then you may need to contact a professional data recovery service such as Drive Savers or Ontrack because there are no third party utilities available to repair APFS volumes since Apple has not released the necessary documentation for the APFS file system yet.

You could try using a data recovery app such as Data Rescue to see if it might be able to access the original macOS volume.

Be very careful making changes to the drive's partitions and volumes as you may make the problem worse.

You should always have good verified working backups. Backups are even more important when making any system changes and especially when using an SSD. It is nearly impossible to recover accidentally deleted files from an SSD plus an SSD can fail at any time without any warning signs.

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