Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

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
Archived

When I try to open Firefox 3.6 (Mac) by clicking on the icon, I get this message: "Close Firefox: A copy of Firefox is already open. Only one copy of Firefox can be open at a time." I've removed older versions and restarted, but still get this message. Wh

AnonymousUser

I've just downloaded Firefox 3.6 (Mac). When I attempt to open, this message pops up: "Close Firefox: A copy of Firefox is already open. Only one copy of Firefox can be open at a time." I've removed older versions and restarted, but still get this message. What's going on?

This happened

Every time Firefox opened

after I downloaded the latest version.

User Agent

Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_3; en-us) AppleWebKit/531.22.7 (KHTML, like Gecko) Version/4.0.5 Safari/531.22.7

I've just downloaded Firefox 3.6 (Mac). When I attempt to open, this message pops up: "Close Firefox: A copy of Firefox is already open. Only one copy of Firefox can be open at a time." I've removed older versions and restarted, but still get this message. What's going on? == This happened == Every time Firefox opened == after I downloaded the latest version. == == User Agent == Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_3; en-us) AppleWebKit/531.22.7 (KHTML, like Gecko) Version/4.0.5 Safari/531.22.7

All Replies (1)

You might find your solution in this article.