I am trying to dual boot Zorin along with Windows 10. During the installation process, I am given the option to install alongside Windows, but the dropdown menu to choose a drive doesn't give me the option to select my C: drive, and installing it on a separate drive would not give Windows the option to boot into Zorin. I have fast startup off. I am not sure what I am doing wrong.
You may want to read over the before you install as this covers windows fast boot and hibernation deactivation (where i think your issue lies).
I also have to ask, how is your drive partitioned? Is windows at the beginning of the drive (second or third partition)? The first will be an efi, then possibly an ms system reserved partition, then windows.
If you want to install Zorin along side of Windows you should create the partition first.
I never ever recommend installing any distro in this manner letting the installer create the new partition.
Make sure bitlocker is off, turn off fast boot in Windows as well as secure boot in your Bios. Go into windows and use the partition manager in Windows and create an empty partition there. You should also do a fix disk in Windows after you do this.
Then fire up Zorin and during the install process choose something else and select the partition you just created in Windows.
I believe there are step by step instructions on the Zorin website on how to do this.
You can use the [HOW TO] Partition & Install Zorin 16 topic as a guide.
I never use the alongside windows option.