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Lenovo ThinkPad T420 with UEFI Only tluck - Open Core Windows Boot Problems

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Big Thanx @tluck for his T420 Guide with Open Core ;-)

I switched from Clover to Open Core.

Changed the Scan Policy in Open Core that it can see my Windows SSD.

Windows is starting perfect when i start it with normal (without Open Core)

When i start Windows out of Open Core Boot Menu Windows restarts after a few Seconds ...

I think this is a Problem with the DSDT ... that Windows take the Open Core DSDT when starting from Open Core Boot Menu.


Anybody knows what a have to change in the DSDT from tluck that Windows is not taking the Open Core DSDT ?


Regards Vicy

I don't think that OC had any impact on your Windows system.

without to knowing the exact details, I guess "Windows system files" are defective.


To repair defective Windows system files, proceed as follows:

Windows includes what is known as a system file checker (SFC) with which you can check the system files and restore them if necessary. You must start the program via the command prompt with administrator rights:

1 Click the Windows Start button at the bottom left of the screen.

2 Enter the command "cmd" in the search field. In Windows 8, type the character string directly on the start screen.

3 Right-click on the search hit "cmd.exe" or "Command Prompt" and select "Run as administrator". Confirm the security question with "Yes".

4 At the command prompt, type "sfc / scannow" and press Enter.

5 Should Windows now discover defective system files, they will be repaired automatically. In most cases the system restores the original file from a cache folder in the Windows directory. In individual cases, however, you will have to insert the Windows installation DVD.


You can also check this EFI folder with yours: https://www.insanelymac.com/forum/topic/315451-guide-lenovo-t460t470-macos-with-clover-and-opencore/

tluck/Lenovo-T460-Clover:  https://github.com/tluck/Lenovo-T460-Clover/releases/tag/v2020.07.25

Thanx for your Help, but when i start Windows without Open Core (give Windows SDD as first boot Device in UEFI) everything is OK no Errors ... so I think it is no Windows Problem ...

It is a T420 and no T460 ... I had taken tLucks Open Core EFI Folder ...


Greetz Vicy

  • 2 weeks later...

Use this config.plist as a guide.


Make sure that both secure boot and TPM are disabled in the bios and that windows was installed in EFI mode or has been configured after the install to boot in EFI mode.  Move the BCD files to the main Windows partition as they are not there by default.  Verify that your machine is booting in EFI mode and not CSM.  Verify that your boot EFI boot partition has boot and ESP flags set.  Make sure you shut down windows while holding down the shift key until completely shut down.

You would do well to use GRUB2 as your main boot loader and chainload windows bootloader and chainload clover or open core to boot macOS.

Your GRUB2 grub.cfg boot entries should look similar to these where xxxx-xxxx is the UUID of the boot partition:

menuentry 'Windows Boot Manager (on /dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-efi-xxxx-xxxx' {
    insmod part_gpt
    insmod fat
    set root='hd0,gpt1'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt1 --hint-efi=hd0,gpt1 --hint-baremetal=ahci0,gpt1 xxxx-xxxx
      search --no-floppy --fs-uuid --set=root xxxx-
    chainloader /efi/Microsoft/Boot/bootmgfw.efi

menuentry "Clover"{
   insmod part_gpt
   search --no-floppy --set=root --fs-uuid xxxx-xxxx
   chainloader /EFI/CLOVER/CLOVERX64.efi    # or whatever path you use

menuentry "Open Core"{
    insmod part_gpt

    search --no-floppy --set=root --fs-uuid xxxx-xxxx
    chainloader /EFI/OC/OpenCore.efi   # or whatever path you use



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