<< Solved >> Windows Partition unavailable after Catalina Update

[UtterDisbelief]

@UtterDisbelief I used the EFI Mounter v3.1 and mounted all disks but there is no "Microsoft" folder. Not in the root folder nor in one of the subfolders. Is it possible to get this folder from someone in the forum or does that technically not work?

Ah, okay. That is what is stopping your drive booting.

As @Going Bald just said, you can use the Windows "Repair" facility to reinstate it. I did this recently for myself using a Windows bootable USB drive (created using the Rufus utility on a Windows PC with the original Microsoft ISO). But if that doesn't work I haven't seen anyone posting a Microsoft boot folder here. It's probably not a good idea anyway as they contain several configuration files. If I remember correctly there is an option in the Windows Set-up to customise a new install and not delete any previously existing data. Check it out as @Going Bald says, but without installing just yet ...

P.S - Disconnect all other drives before trying any re-install or the boot files will get put on the wrong drive.

 

[EmanuelTheDude]

@UtterDisbelief Not sure if it helps but in Mac OS I can see the content of my windows drive. Could the data be on the drive somewhere? Or could I somehow rename the drive there and enable the owner?

 

[UtterDisbelief]

@UtterDisbelief Not sure if it helps but in Mac OS I can see the content of my windows drive. Could the data be on the drive somewhere? Or could I somehow rename the drive there and enable the owner?

No, the "Microsoft" boot folder is in the EFI partition of the drive, just like we put the Clover EFI folder in a Hackintosh EFI partition. It's not visible in a normal disk view. You need to mount the drive's EFI partition and look there

 

[EmanuelTheDude]

@EmanuelTheDude
Can you boot the Win10 installer USB/DVD?
If you can, do so, and instead of clicking the install button select from lower left corner repair button and follow screen prompts.

I created a bootable Windows 10 USB Stick and tried the repair function. The system then says it cannot repair anything

At the moment I have 2 SSDs. One with Mac OS and one with this broken Windows. Instead of repairing the windows SSD I could also reinstall it, right? Or is it easier to reinstall both, Mac OS and Windows?

 

[UtterDisbelief]

I created a bootable Windows 10 USB Stick and tried the repair function. The system then says it cannot repair anything

At the moment I have 2 SSDs. One with Mac OS and one with this broken Windows. Instead of repairing the windows SSD I could also reinstall it, right? Or is it easier to reinstall both, Mac OS and Windows?

Yes, you can re-install Windows. I never like to make recommendations like that as too much can get lost - including Activations. So that's has to be your choice.

If you do re-install then remember to disconnect all the other drives, or the Windows Boot Manager will get put on the wrong one - it is bound to happen.

You should not need to re-install macOS as long as it's EFI folder is intact

 

[Big-W]

You can create a bootable EasyBCD usb and try that to make Windows bootable again if you dont want to reinstall. Just unplug your OSX drive first.

 

[Going Bald]

I created a bootable Windows 10 USB Stick and tried the repair function. The system then says it cannot repair anything

At the moment I have 2 SSDs. One with Mac OS and one with this broken Windows. Instead of repairing the windows SSD I could also reinstall it, right? Or is it easier to reinstall both, Mac OS and Windows?

Disconnect the Mac OS drive for safety - it is not necessary to re-install it.

If you have no files or apps needing backup you can go ahead and re-install Win10.

 

[EmanuelTheDude]

This thread can be closed.
As a solution I copied all files that I needed off my Windows SSD and then reinstalled Windows completely. As mentioned above I disconnected my Mac OS Drive for safety. Everything works well now.
Thanks for the big help to everyone here!!! I'll have a drink on you! Cheers!