Here is a breakdown of why this happens and how to bypass it.
Before fixing, verify the current configuration using Windows Setup or command line:
If you prefer not to delete partitions manually, or if the method above fails, you can force the drive to convert using the Command Prompt.
If you are trying to install an older version of Windows or have specific boot requirements, the issue might be your motherboard settings, not the drive itself.
If partition style mismatches boot mode: