PS 2024 "disk is locked" popup when attempting to save a copy of a file using a custom plugin.

This post is for "disk is locked" not "file is locked".  

What can cause the "disk is locked" popup?

I have searched web and not found helpful posts yet.

My company has older photoshop custom plugins (Windows & mac versions) that opens & saves a file in a custom format (auto & format plugins)  (developed with CS5 & CS6 versions of PS) prior to the Creative Cloud releases .  

It has worked on both mac and windows  until recently. We had to do some work to get the plugin to work on latest Mac updates using Rosetta.

We have started getting a "Could not save a copy as "somefilename" because the disk is locked."

This plugin works on Mac, and we do not get this error on the mac.

This plugin does not work on Windows.

We can open the file in the custom format without any issue. When saving the file we have an option to compress the file. When this option is selected, we get the "disk is locked" popup.  If we save the file without compressing, we do not get the popup.

Does anyone have any knowledge of what might cause this popup?