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MacOS and windows not booting anymore after deleting EFI partition

Hello together,

I recently reinstalled my bootcamp-partition (was 750gb macOS / 250gb Windows first) using the bootcamp software on macos. everything worked out great, till I noticed macOS only having 500gb storage and windows using the wanted 250gb. So the last 250gb were like „gone“. In Windows i saw unused space on the SSD, but I couldn‘t resize the macOS partition because I would have to move it first. 

I also saw a OSXRESERVED partition and some 16mb partition (that was probably the EFI), so I deleted both, booted into Gparted via a live USB and moved the bootcamp partition to the right.

Restarting to macOS, i saw the free space and resized my macOS partition to 750GB, but from then macOS wasn‘t shown in the boot-selector and windows doesn‘t boot (only a blackscreen).


How can I fix this? Do I have to reinstall everything? Can I recreate the EFI-Partition?

My specs:

  • Crucial P2 1TB SSD
  • Macbook Pro 2015 15“
  • macOS monterey / Windows 10 (everything latest)


Thanks for your answers.

MacBook Pro 15″, macOS 12.6

Posted on Apr 28, 2023 6:32 AM

Reply
Question marked as Top-ranking reply

Posted on Apr 28, 2023 7:11 AM

Very much agree with @BobTheFisherman suggestion and start over from a Clean Installation of macOS First then then use Bootcamp there after.


The article from Apple seems to clearly imply the computer must First Have a functioning version of macOS before Bootcamp can be used.


Changing the Partition Map Structure by another other means is not suggested - period.



Scorched Earth Method 


This method will WIPE ALL Data and there is No Data Recovery - Period.


>> Only works on Intel Based Apple Computer <<


To perform this action will require booting from a Bootable Installer


The Bootable Installer can Only be performed on an Apple Computer 


This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Big Sur would have to be done on a computer that Qualifies to run Big Sur.


Notation: If the computer being used to perform this action is Too New or Too Old to qualify to run the version of macOS - this computer can not be used.


Alternative is, to gain access to a Qualifying Apple Computer from a family member, friend or associate.


Extra Special Notation regarding the Touch ID equipped Apple Computer.


 About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting 


1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.


2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive. 


3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives. 


4 - Choose the Upper Most Drive ( not the volumes indented and list below ).


5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map. This applies to macOS 10.14 Mojave and above. 


5A - Formatting for macOS 10.13 High Sierra and below requires HFS Journaled with the GUID Partition Map


6 - Once that is done >> backup out of Disk Utilities and choose install macOS. 


7 - Follow the prompts and it may automatically reboot several time. 


8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.



Similar questions

3 replies
Question marked as Top-ranking reply

Apr 28, 2023 7:11 AM in response to lontage

Very much agree with @BobTheFisherman suggestion and start over from a Clean Installation of macOS First then then use Bootcamp there after.


The article from Apple seems to clearly imply the computer must First Have a functioning version of macOS before Bootcamp can be used.


Changing the Partition Map Structure by another other means is not suggested - period.



Scorched Earth Method 


This method will WIPE ALL Data and there is No Data Recovery - Period.


>> Only works on Intel Based Apple Computer <<


To perform this action will require booting from a Bootable Installer


The Bootable Installer can Only be performed on an Apple Computer 


This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Big Sur would have to be done on a computer that Qualifies to run Big Sur.


Notation: If the computer being used to perform this action is Too New or Too Old to qualify to run the version of macOS - this computer can not be used.


Alternative is, to gain access to a Qualifying Apple Computer from a family member, friend or associate.


Extra Special Notation regarding the Touch ID equipped Apple Computer.


 About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting 


1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.


2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive. 


3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives. 


4 - Choose the Upper Most Drive ( not the volumes indented and list below ).


5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map. This applies to macOS 10.14 Mojave and above. 


5A - Formatting for macOS 10.13 High Sierra and below requires HFS Journaled with the GUID Partition Map


6 - Once that is done >> backup out of Disk Utilities and choose install macOS. 


7 - Follow the prompts and it may automatically reboot several time. 


8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.



MacOS and windows not booting anymore after deleting EFI partition

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