Creating a Shared Folder between your Mac running Catalina and a Virtual Machine

The purpose of a creating a shared folder is to transfer documents between your Mac running Catalina (HOST) and the VirtualBox virtual machine (GUEST) running Mojave versions of Screenwriter 6.5 and/or Dramatica Story Expert 5.3.   Once you follow these steps and set this up, you won't have to do this again.

Here are the one-time steps to create the shared folder:

1. Create a folder on the Host, preferably in an accessible directory like "Documents".  For example "My Transfer Folder".
   
   
   
   
2. Use the Apple > Preferences menu command to open the Host computer's preferences:
   
   
   
   
3. GO into the HOST's SHARING preferences:
   
   
   
   
4. Select File Sharing checkbox and then select that entire row:
   
   
   
   
5. On the right will be a two-column browser.  The first will say "Shared folders".  Click the "+" to add "My Transfer Folder". When you click the "+", you'll need to locate the "My Transfer Folder", select it, and press the Add button.
   
   
   
   
6. IMPORTANT: below where it says "File Sharing ON", you'll see something like:
   
   "Other users can access shared folders on this computer, and administrators all volumes, at "smb://192.168.23.60" or "afp://macbook-pro-7":
   
   
   
   That last address is essential. Copy it down somewhere because you'll be referring to it shortly in step #9 and copy/paste won't work.  Make sure to include the "afp://" or "smg://" part of the volume name with the rest of it.
   
   
7. If it is not running, launch VirtualBox and the virtual machine running Mojave (GUEST).
   
   
8. On the GUEST, in the Finder use the GO > Connect to Server menu command. 
   
   
   
   
9. Enter the address is you saved from step #6:
   
   
   
   
10. Now press Connect.  You may be requested to log into your HOST computer.  Change the name from "virtualmac" to your host computer's login name and password.
    
    NOTE:  You can either user your long user name, or your short user name, which is the name of your Home folder.  If you're still unsure, simply go into the Finder on your CATALINA HOST and select GO > Home.  At the top of the window that just opened will be the SHORT user name.
    
    
11. You'll be presented with a list of shared folders from the Host. Select the folder "My Transfer Folder" and press OK.
    
    
    
    
12. The transfer folder will mount.
    
    
13. We suggest dragging the Transfer Folder Window's "proxy icon" (to the left of the window title)...
    
    
    
    ... to the area to the RIGHT of the dividing line in the Dock in the Favorites section.  This makes a convenient alias for mounting the folder across restarts.
    
    Once mounted, you'll see "My Transfer Folder in the LEFT "Sidebar" area of all Finder windows:
    
    
    
    

That's it!

Alternatively, you can share documents using Dropbox.

LINK:  Adding Dropbox to VirtualBox workaround for Mac Screenwriter and Dramatica Story Expert