Hi, please check if you are clean from any influences that could start that : https://www.malwarebytes.com/mac/

Wouldn't ESET be just as good as malwarebytes?

Also, my research indicates that Firefox has had this exact problem before, and a fix was issued in an update from Mozilla back then.

You get tabs opening endlessly if you select the Firefox program to handle a file when you get an "Open with" dialog.

Check the Mailto application in Firefox > Preferences > Applications Make sure it isn't set to the Firefox application because Firefox can't handle the mailto protocol internally and you will get tabs opening endlessly.

• https://support.mozilla.org/en-US/kb/Firefox+keeps+opening+many+tabs+or+windows
• https://support.mozilla.org/en-US/kb/change-firefox-behavior-when-open-file

That fixed it! You have to manually select a mail client other than "Firefox" in Firefox > Preferences > Applications (as described above) to make this problem stop. I just tested it on some mailto: links and the problem is gone-- thanks, cor-el!

Is there a resolve for those of us that use Gmail (pinned tab)?

EDIT: Never mind. Seems this is already an option.

Firefox > Preferences > Applications > Mailto: > Use Gmail

Works like a charm! :)

Matt said

Is there a resolve for those of us that use Gmail (pinned tab)?

Ah! Never mind. Seems this is already an option in Firefox > Preferences > Applications > Mailto: > Use Gmail

Works like a charm! :)