Can't boot from M.2 with Windows installed

[Moyomo]

So yesterday I got a new case and so i removed my hardware from the old case and put it in the new one.

In the BIOS all of my drives are shown correctly but  when i try to boot from my m.2 (even through boot menu) where windows is installed it says:

"Reboot and select proper boot device. or insert boot media in selected boot device and press any key"

i tried to boot from a windows installation USB and start cmd. In there i can access the drive and see all the files on it, so the drive is not corrupted.

I also tried to activate the partitions with diskpart but it just said something like "can't activate. this only works with MBR drives".

Activating partitions works with all my other drives without any problems. so it seems like the m.2 is somehow partitioned (?) in GPT.

Is there a fix for this problem? Because I don't think I can change the partition style from GPT to MBR without deleting all the files on it.

[Applefreak]

First check the bios and see if there is an option for legacy os or something like that enabled. It should say something about GPT in the description, make sure to have it set to that or if you have mixed drives sometimes there is an option for both.

 

One other thing to consider is that when switching hardware, windows may need a reinstall or at least a repair install, due to different drivers and kernel configs necessary. You can change to partition table to MBR if you like with dispart but I would advise against it as long as you have valuable data on it. Usually a fresh install is the best solution.

[Moyomo]

3 minutes ago, Applefreak said:

First check the bios and see if there is an option for legacy os or something like that enabled. It should say something about GPT in the description, make sure to have it set to that or if you have mixed drives sometimes there is an option for both.

 

One other thing to consider is that when switching hardware, windows may need a reinstall or at least a repair install, due to different drivers and kernel configs necessary. You can change to partition table to MBR if you like with dispart but I would advise against it as long as you have valuable data on it. Usually a fresh install is the best solution.

Alright I'll try that, thank you.

I didn't change the hardware except for the case, so it should work in theory

[Applefreak]

Well that is kind of strange then. Maybe reset the bios (clear cmos). Usually if nothing changed in terms of hardware, it should work. I guessing you haven't moved the M.2 drive to a different slot, right?

Try a repair install first and see if it can fix the problem.

Make sure that there is nothing else plugged into the motherboard like new RGB controllers or card readers and stuff like that.

[Moyomo]

2 hours ago, Applefreak said:

Well that is kind of strange then. Maybe reset the bios (clear cmos). Usually if nothing changed in terms of hardware, it should work. I guessing you haven't moved the M.2 drive to a different slot, right?

Try a repair install first and see if it can fix the problem.

Make sure that there is nothing else plugged into the motherboard like new RGB controllers or card readers and stuff like that.

no i haven't moved the M.2. Clearing CMOS also didn't help.

When booting in legacy mode i didn't even get to the BIOS (which is super weird) so I had to reset it.

i unplugged everything except the monitor and keybaord but still the same result.

i saved my important files through cmd and now i'm just gonna reinstall windows (after manually setting the m.2 to MBR)

 

thanks for your help anyways