AllSync & AllDup

When clicking on a pdf Group the preview pane shows nothing. It should use Internet Explorer to view pdfs but on my Windows 11 machine I only have the newer Edge. So I think I either need to persuade it to use edge or I'd like to add a pdf browser as a separate plugin, I have PDF24 installed.

Can someone tell me how to proceed.

Many thanks for a great product, I didn't realise how many duplicate files I have.