"Steam failed to load: *SteamStartEngine(0xbfffdf54) failed with error 1: A Steam Engine Instance already exists"

My Mac Steam installation on 10.7 has started giving this "failed to load" dialog whenever I try to launch Steam.

I have tried deleting the Application Support folder which allowed Steam to launch but then I had to redownload the games again, and I have a feeling that it is handling the symptom, not the cause.

What is the reason (what does Steam check for, so I can look) and how do I fix it?

Solution 1:

This is caused by a component of Steam not stopping correctly, and then when you try and reopen Steam it complains.

Open a terminal window and run the following command (type it in and press enter):

    ps -A | grep Steam

This will give you a list of running programs that have the word 'Steam' in them - usually 2 or 3. When I had your error and ran the above command this is what I saw:

    712 ??       700:23.42 /Applications/Steam.app/Contents/MacOS/osx32/steam -psn_0_40970
    64849 ttys002    0:00.00 grep Steam

One of the items will be called 'grep Steam' - ignore that one. Each item in the list will have a number - this is the first piece of text on each line. The number we are interested in here is 712.

Run the following command to close the lingering Steam component:

    kill 712

Where you replace 712 with whatever number you found. If there was more than 1 number, run kill again with the other numbers too.

You should now be able to close the terminal, and run Steam just like normal. :-)

Solution 2:

Found something that sounds promising in a thread posted to steam official forum:

Please exit Steam and go to the folder Users/[username]/Library/Application Support/Steam

Delete all of the files in this folder.

Then, you will need to launch Steam.app from your Dock or Applications folder.

With Steam running, re-test the original issue.

Note: This process will not affect your currently installed games.