I'm using TexShop 4.24 and pdfTeX on macOS 10.14.3
In the past, when i click on 'typeset', or Command T, a preview window of the pdf pops up. However, recently when clicking on 'typeset', i get the pop up to save the file as a pdf.
If i open my old files, the 'typeset' button works to open a preview. New files face the issue above though.
Would appreciate any advice!