Unable to "save as" or "export as"

New problem today - when opening images and trying to "save as" or "export as" - the file settings, image size, canvas size and "cancel"/"export" buttons are no longer clickable, so I can't currently optimise images. I have to close the dialogue window.  This started today, in photoshop 2022, and is continuing after updating to 2023. Anyone else having this issue or know of a cause/fix?