There’s nothing to ‘open’ and pointless to double click on the plug-in’s. Once all the security mess is cleaned up, you open an image in Photoshop and select the plug-in from File>Automate. Again, works on this end after getting past Catalina’s security configurations.
Yup, been using it for years. But whenever I tried to "open" to get past the lockdown it would launch Ps, then give me the incompatibility message.
I finally got it. Not sure what I was missing before. I used the terminal, following these instructions for getting the plugins past Catalina security. These are for InDesign, but they work for Ps as well. All is good:
"You will need the admin password later on.
Quit InDesign.
Move the plugin out its place, e.g. to the Desktop.
Start InDesign, so that it considers the change
Quit InDesign.
Move the plugin back.
Launch terminal
type "sudo xattr -r -d com.apple.quarantine " without the quotes and without return, but including the final space
Instead of typing the path, drag the plugin file to the terminal.
The result should read:
sudo xattr -r -d com.apple.quarantine path/to/your/plugin
press return to run the command
terminal will ask for an admin password.
When completed, start InDesign."
Do this for each plugin in the package (repeating the terminal steps). Terminal will ask for your admin pw for only the first one.