Images not showing in Viewer

So that I can keep using Aperture, I've created a virtual machine on my iMac running Mojave 10.14.6 using Parallels. I've installed Aperture and opened existing Library which is stored on host OS on iMac running 10.14.6 currently. (Eventually I plan to update host OS to Catalina, once I get Aperture working properly on VM.)

Unfortunately when I open the Library on VM I can't see any images in Viewer and obviously I can't edit any of the photos in the Library. However I can see all images and projects in Browser and the Browser window on Split View. If I double-click on an image in Browser, the Viewer window opens, but nothing is there. When I click on an image in bottom pane of Split View, the top pane shows nothing. . . Sometimes if I select an additional image while holding shift key, the second image pops up on the screen and then immediately vanishes . . . I still have Aperture on the host OS, and it still works perfectly. I'm careful not to have both instances running at the same time.

Is there some setting for the window(s) in Aperture that I don't have set correctly to allow me to see images in the Viewer? Must I move the entire Library to the VM, so that the images will be visible and available for editing? Any suggestions would be appreciated!

Thanks for your help,

Chris