Do you start firefox with any command line parameter?

This is an indicator that the browser is being controlled from out-of-process, e.g. when Marionette or the remote debugging protocol is used.

I start FF with icon on my task bar. How is someone/something able to control my browser? HOw do I stop it?

I start FF with icon on my task bar.

Right-click that shortcut, click Properties, then Windows should display the dialog with the Shortcut tab focused. What does the Target line say? Here's what is normal for 64-bit Windows -- no extra stuff:

"C:\Program Files\Mozilla Firefox\firefox.exe"

Oh, if it's a pinned shortcut, there are two right-clicks:

Right-click the button, then right-click Mozilla Firefox, then right-click Properties.

This message just started happening: "Browser under remote control (reason dev tools)." There is a robot in the left side with red and grey stripes.

I am so confused I've tried all the suggestions above. What is it? Why did it just start happening? Is my security compromised? Firefox you really need to put something out about this especially for those who are not tech savy.

Did you confirm that the shortcut you use to start Firefox doesn't have any command-line switches?

Like others, every time I restart firefox it's under remote control - devtools. I tried to delete the user.js file and create my own. I tried to use about config to reset dev tools to: devtools.chrome.enabled false devtools.debugger.prompt-connection true devtools.debugger.remote-enabled false

but they revert back to true, false, true.

I changed them in my profile too, but they re-set in there also

I have tried to reinstall firefox multiple times. Please help.

Does the user.js file that set these prefs reappear if you remove this file ? Normally deleting this user.js file and resetting the involved prefs on the about:config page should be sufficient.

If that doesn't work then try to set the prefs via user.js to their default values and make the file read-only.

• devtools.chrome.enabled (false)
• devtools.debugger.prompt (true)
• devtools.debugger.remote-enabled (false)

You can do a malware scan just to be sure.

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware