21.04 install DVD activity

[xeddog]

I am trying to install Ubuntu 21.04 as a Virtualbox guest vm on a Ubuntu 20.04 host. With the host machine booted all the way, I insert the dvd, wait for it to get mounted, and then launch the guest machine. As soon as I do that, the dvd reader (actually a LG Blu-ray burner) just starts hammering away at something. It sounds like the read/write head is just bounding back and forth for 10-15 minutes before anything happens. Eventually, the live cd boots and I can start the install. Any ideas what is going on???

I can also burn a 20.10 dvd using the same hardware, same software, same dvd's, etc. and it will install "normally" without the 10-15 minutes of the head banging around in the dvd drive. I have re-downloaded the image from Ubuntu 4 days later, and burned a new dvd with the same result.

[ActionParsnip]

You don't need to burn any media to boot in Virtualbox. Virtualbox can read ISO files in your Windows file system. No media is needed. Did you make the DVD yourself or did you get it from a friend?