Mounting not working

Does anyone know how to solve this issue? I keep getting this error and I’m not sure why. I’ve never installed this before so it’s especially confusing.

Hello and welcome,

Is this an ISO?

Which one or where from?

Was it verified?

And how was it written?

This is my first-time install using the Desktop ISO downloaded from the official CachyOS website. I didn’t verify the checksum before using it. I’m booting it via loopback from my existing GRUB rather than writing the ISO to a USB, so I didn’t use a USB writing program.

I see .. and how was this done?
Has the method proved workable in other instances?

I’m using a custom GRUB menuentry to boot the ISO directly via loopback from my existing system. This is my first time trying this method with the CachyOS Desktop ISO, so I don’t know whether it’s a supported or working method in this case.