Along with a black screen and a message that no bootable medium is found.The image file 'C:\Users\micha\Documents\Windows.iso' is inaccessible and is being ignored. Please select a different image file for the virtual DVD drive..
Here are the steps to reproduce:
1. I had an existing VB with a Windows VM (that I was having an obscure timing problem on and couldn't fix)
2. Moved the VM to a new SDD
3. Updated VB by reinstalling
4. Made a new VM according to a tutorial (that I can't post yet, but it's called "How to Install Windows 10 in a Virtual Machine" on Extremetech.
5. Downloaded the Windows 10 installation media tool, selecting "using the tool to create installation media."
6. Selected "ISO" file
Which brings us to the error message.
The Windows.iso file is 4.5GB and I can see it in the Downloads folder.