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Downloading Firefox

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I have been using Firefox for a few years now and love it. Before Christmas, I bought a new computer (Apple Mac) and my old Mac, with Firefox operational, was passed to my husband. The new Mac had Safari installed as the browser but I didn't like it and downloaded Firefox to use instead. It downloads fine but when I try to open it, I get a message stating "A copy of Firefox is already open. Only one copy of Firefox can be open at a time". There is no other Firefox open. I've done a search on the computer for any files with Firefox of Mozilla in their name and deleted them (including emptying the waste basket), then downloaded again but still get the same error message. I've tried this several times, both with the old computer connected via network and with it disconnected but always the same message. I've tried to persevere with Safari in the hope it will grow on me but it hasn't and now I'm desperate to re-install Firefox. Today, my husband's Mac crashed completely and I've had to erase it and re-install the software so he no longer has Firefox on his computer either and I thought that would be an opportunity for me to re-load it on my computer but I'm still getting the message that Firefox is already open.

I have been using Firefox for a few years now and love it. Before Christmas, I bought a new computer (Apple Mac) and my old Mac, with Firefox operational, was passed to my husband. The new Mac had Safari installed as the browser but I didn't like it and downloaded Firefox to use instead. It downloads fine but when I try to open it, I get a message stating "A copy of Firefox is already open. Only one copy of Firefox can be open at a time". There is no other Firefox open. I've done a search on the computer for any files with Firefox of Mozilla in their name and deleted them (including emptying the waste basket), then downloaded again but still get the same error message. I've tried this several times, both with the old computer connected via network and with it disconnected but always the same message. I've tried to persevere with Safari in the hope it will grow on me but it hasn't and now I'm desperate to re-install Firefox. Today, my husband's Mac crashed completely and I've had to erase it and re-install the software so he no longer has Firefox on his computer either and I thought that would be an opportunity for me to re-load it on my computer but I'm still getting the message that Firefox is already open.

Modified by aileenmproud

Chosen solution

Try to remove the old left over folders in your Library folder: There are folders "Firefox" and folder "Monzilla" sitting in your Library/Application folder. Trash them and reinstall Firefox and see if it works.

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All Replies (6)

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Download Firefox from http://www.mozilla.org/en-US/firefox/new/ Save it to your desktop Restart your computer Run the installer

What happens?

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I got the same message: A copy of Firefox is already open. Only one copy of Firefox can be open at a time. Don't know if it's relevant but I no longer get the option where to save downloads - they just go straight to a download folder - so I dragged it out of the folder onto the desktop then restarted, then ran the installer as instructed and got the message detailed above. Thanks for your interest.

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Chosen Solution

Try to remove the old left over folders in your Library folder: There are folders "Firefox" and folder "Monzilla" sitting in your Library/Application folder. Trash them and reinstall Firefox and see if it works.

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Do you have a file profiles.ini ?


Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

See also:

Modified by cor-el

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Each time I've tried to solve the problem, I've got the computer to search for anything containing firefox or mozilla (both in the name and the contents), then I've trashed everything it's found and emptied the trash. After I received your post, I tried again but the same thing still happens. I've looked in the library and there's no folder there with either Firefox or Mozilla in the name. Surely the computer 'find' facility would come up with the rogue file/folder if it had either Firefox or Mozilla in its name? Could it be inside one of the library folders? Incidentally, sorry for the delay in reviewing your message - got a sudden urgent job to do for a client.

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I've done a search for these items and nothing's come up. Creating a new profile sounds complicated and I've just been landed with some urgent work for a client so I'll have a look at your suggestion when I get chance. But thanks for your help.