Firefox: Annoying reset request

When Firefox wants to reset to default configuration, but You don't want to

Sometimes Firefox wants to be all nice and helpful but only gets to annoy you with some popups. This time the fox wants to reset your configuration to default values. You have three options in this case:

1. Ignore the hell out of it
2. Give in, follow up the request and reset that damn thing or
3. Read this guide to get rid of the stupid popup!

You have chosen option 3? Great! Now listen closely. Here are the instructions:

• Close Firefox. You don't need it right now.
• You want to open a terminal with Ctrl + Alt + T
• Type:

 cd ~/.mozilla/firefox/

• Press Enter to enter the directory.
• Now type:

 ls -la

• It should look like this screenshot XY.
• You should see the line with <RANDOM CHARS>. default as marked in the screenshot.
• Now move to this folder with:

 cd <RANDOM CHARS>. default/

• If you type ls -la now, your terminal should give this output (screenshot XY).
• You want to remove .parentlock with

 rm .parentlock

Congrats! Firefox now should leave you alone. You did well! Grab some coffe and have a nice day.