Hi mattymoe, Firefox handles PDFs and some other web content types specially. I apologize that the following is long, but I wanted to provide some more background and options for opening/saving PDFs. '''''Using the'' "Open in Firefox" ''option for PDFs''''' Firefox can't display PDFs without downloading and saving them ''somewhere.'' You can tweak some hidden settings to determine ''where'' Firefox saves the file, whether that is the web content cache, the "Save files to:" download folder, or the Windows Temp folder. Here are the slightly messy details. '''Background: inline vs. attachment disposition''' If web servers don't specify how Firefox should handle a PDF, or if they specify "inline" handling, then then Firefox loads the PDF as web content with its original URL in the address bar. The PDFs are saved with other cached web content, not in your download folder. This is good. But web servers can try to force a download by setting Content-Disposition: attachment if they don't want browsers to show the files in a tab. In this case, Firefox auto-saves in your "Save files to:" folder before opening the saved PDF in a new tab. '''Options for saving PDFs''' '''(1) If you prefer to preview in Firefox: always cache them (override "attachment" disposition to "inline")''' Here's how you set this up: (a) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button accepting the risk. ''More info on about:config:'' [[Configuration Editor for Firefox]]. ''The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future. I'm using this so I feel comfortable mentioning it.'' (b) In the search box in the page, type or paste '''browser.download.open_pdf_attachments_inline''' and pause while the list is filtered (c) Double-click the preference to switch the value from false to true '''(2) If you prefer to save externally without previewing: use Always ask (or Save File)''' This article describes how to select those options for the Portable Document Format file type: [[Manage file types and download actions in Firefox]]. Does either of those work the way you prefer?