Adding to Archives

I have created a zip archive using Directory Opus and an now attempting to add files and folders to at with Directory Opus by drag-and-drop. Whenever I try to do this I get the message "An error occurred copying 'file_01': The archive is write protected". I see no write protection on what is being copied or on the zip file by in properties. Can you assist? I have Directory Opus 11.17 x64.

Is Preferences / Zip & Other Archives / Zip Files / Open Zip files as read-only by default turned on?

Turn if off and then fully exit Opus (via File / Exit Directory Opus).

It was and when turned off the problem is corrected. Thank you Leo.