A common theme of the problem was that because Parallels Tools was not installed, access to the host could not be established, and the screen resolution only offered 1024 x 768, which I had not mentioned.
I really needed to get Parallels Tools installed, but the inability to mount the virtual CD was blocking that. I found a Parallels knowledge base article that said the the system automatically mounts it. Speciically it said "When macOS boots up, choose Actions > Install Parallels Tools. The Parallels Tools ISO image gets connected to the virtual machine CD/DVD drive. The guest OS mounts it automatically." This was not happening.
On a hunch, I told the CD device to unmount the prl-tool-mac.iso using the Disconnet choice on the dialog shown in the screen shot:
Here are my steps:
- Keeping the configuration window open, I first shut down the VM (because some things cannot be changed until the VM is shut down). I don't know if this was necessary, but it is the way I did it.
- Then I disconnected the ISO image.
- Then reconnected the ISO image.
- Then started the VM.
This time the CD device was there right on the desktop, and I was able to click it to install Parallels Tools.
After getting Parallels Tools installed, all the problem listed in my original question went away: - the guest could see the host file system; - drag and drop between the guest and host is possible; - clipboard can be shared between the two - and probably several other actions that I did not try would also be available, such as restoring from a Time Machine backup or cloned image; - screen resolution went to normal.
To summarize, if the Parallels Tools CD image does not mount, disconnect it and reconnect it, with the possible requirement for the additional intervening steps described above.
Last edited by a moderator: Apr 14, 2020