My Dad recently upgraded to Lion only to discover that Logic Pro 8 no longer works on it. When he opened the application it just pops up with message saying that Logic was not compatible with this version of OS X, and promptly quits.

I saw some workarounds on you tube and other sites that involved starting Logic up on the command line by calling the internal binary inside the Logic app package directly – but this “fix” was not clean as it requires the terminal window to stay open and it also allows you to open logic twice or three times by accident and have it running it multiple processes (not a good thing). It also prevented Logic from working nicely with the rest of the OS because you still couldn’t open the app directly the “normal” way.

So I found a fix that will actually allow Logic 8 to work normally on Lion (i.e. you can just open it using the regular application icon and there’s not command line stuff involved).

Steps:

1. Right click (or control-click) the Logic Pro 8 application icon and select “Show Package Contents” from the contextual menu that appears. This will open a folder with the contents of the application package.
2. Open the “Contents” folder.
3. Open the Info.plist file in Text Edit. (You should be able to just double click it). This will open a big XML file with a whole bunch of directives.
4. Look for the text:

<key>LSRequiresCarbon</key>
<true/>

Delete this text.

5. Save the file.

You should now be able to open Logic Pro 8 normally on OS X Lion.

Special Note: That directive says that Logic requires the Carbon libraries to be installed. Carbon is old and it doesn’t look like Logic actually uses it at all – this is just a legacy restriction – I think. That said, it is possible that there are some features that still rely on Carbon to be there and may not work correctly on Lion. I’m sure my dad will let me know if he runs into any problems. So far everything appears to be working properly.

Edit: Apparently updating Lion to 10.7.2 also fixes this issue so you don’t need to perform this workaround.