Windows 10 on a 2011 iMac running catalina

[jumpncrash]

Hey guys, how are you all doin.
I'm kind of a mac noob, but I have been working on a 2011 iMac 27" trying to get it upgraded to last a while longer, I threw in a new GPU (wx7100), i7 CPU, and 2TB SSD, and then installed Catalina on it.
Now come the problems, I wanted to get a dual boot going on it, but from what I understand the 2011 doesn't have win10 support(whatever that means), and catalina doesn't do windows 7 in boot camp.
I have created a windows 10 install DVD(because from I have read it can't be installed using USB because it will default to EFI) and gotten it to boot and load into the windows installer, but once I get into the partitioning utility of the windows installer I get an error about not being able to install to an MBR disk on an EFI system.
Oh! and the windows install is going on a second SSD that was already in the system

Does anybody know what I need to do to get around this? Maybe point me in the direction of a guide or something, I'm sure it's a common issue but my google-fu isn't doing its job today.

 

[ptfuzi]

I guess that with paragon disk manager y I u can convert your disk to gpt. Just make sure to have a backup

 

[jay508]

UEFI must be installed on the GPT format hard disk. There is another method that USB PE boot can be installed on the MBR format hard disk. I have tested all of these, but installing the latest version of windows 10 Pro 1909 sound card can not work normally without sound. I don't know how to solve the problem. Windows 7 installed in MBR partition table format works normally. Use UEFI + GPT to install Windows 7 After the release, the System rebooted and the main card was blocked. The black screen did not find the reason.

 

[krazzix]

This is the only solution that worked for me:

How to convert a drive from the GPT format to the hybrid GPT/MBR format when using High Sierra (macOS 10.13.2)

Previous versons of OS X and macOS automatically converted pure GPT drives to hybrid GPT/MBR format when the 2nd, 3rd, and/or 4th GPT partitions were formatted "MS DOS (FAT)" by the Disk Utility

apple.stackexchange.com

 

[Nguyen Duc Hieu]

You can run a Windows 10 on and external USB box.
Obtain a windows 10 ISO.
On a windows PC, use Rufus to create a WindowToGo disk to that External USB Box.
Plug it in the iMac and try to select the USB box as boot device. (Hold Option at start-up)
Install drivers for windows from then.