Unable to open scanned single page

Architect 6 on Win10(64bit) - after scanning a single page and saving to desktop I am unable to open the pdf. However when I scan multiple pages, the pdf opens but I lose the last page.

To isolate the issue by process of elimination, I emailed the same scanned pdf to another PC opening it with Nitro10 & Adobe Reader which it did successfully, this rules out any printer/scanner error.

A strange one?