I want to use a command option to open a new '''blank''' tab in a specified portable instance of Firefox using a specified profile. I constructed my command like this: "Path-to-Firefox-executable" -profile "Path-to-Profile" -new-tab "about:blank" It partially works (it opens the correct instance of Firefox and uses the correct specified profile) however it always opens ''about:newtab'' instead of ''about:blank''. Seeing as I am specifying the exact page to open, any New Tab settings in the browser should not matter, and I should just get the page that has been specified in the command. If I manually type about:blank into the url bar, then a blank page opens as expected, so the url is correct, it just won't work for me as part of the above command line. Does anybody else have this issue? How can I get this to work correctly?