We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Can't open new tabs in Firefox from the command line on a Mac

  • 2 replies
  • 1 has this problem
  • 9 views
  • Last reply by cor-el

bronco_popsicle
bronco_popsicle
more options

If I run 

   /Applications/Firefox.app/Contents/MacOS/firefox -new-tab https://www.mozilla.org

when Firefox is already running, I get the error "A copy of Firefox is already open. Only one copy of Firefox can be open at a time." It is true that Firefox is already running, but what I am shooting for is getting a new tab in the already running instance, as the -new-tab flag indicates. I get this problem even if the already running instance was started with exactly the same command.

Some of the flags at https://developer.mozilla.org/en-US/docs/Mozilla/Command_Line_Options explicitly say they open new tabs or windows within an existing instance of Firefox, such as -private-window, but I get the same behavior with those flags. What am I doing wrong?

If I run /Applications/Firefox.app/Contents/MacOS/firefox -new-tab https://www.mozilla.org when Firefox is already running, I get the error "A copy of Firefox is already open. Only one copy of Firefox can be open at a time." It is true that Firefox is already running, but what I am shooting for is getting a new tab in the already running instance, as the -new-tab flag indicates. I get this problem even if the already running instance was started with exactly the same command. Some of the flags at https://developer.mozilla.org/en-US/docs/Mozilla/Command_Line_Options explicitly say they open new tabs or windows within an existing instance of Firefox, such as -private-window, but I get the same behavior with those flags. What am I doing wrong?

All Replies (2)

bronco_popsicle
bronco_popsicle Question owner
more options

It appears that as of five years ago this was a known bug with no intended fix: https://bugzilla.mozilla.org/show_bug.cgi?id=393645

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

Try: