Every 10 seconds, I get this message a few times in Console:

27.08.11 16:40:21,034 osascript: Performance: Please update this scripting addition to supply a value for ThreadSafe for each event handler: "/Library/ScriptingAdditions/SIMBL.osax"

I wonder what it means and what I am supposed to do.

Also, what can I do (except of uninstalling SIMBL) to make SIMBL stop spamming the system logs?


You installed SIMBL, a tool for patching applications at runtime. Mac OS X isn't happy that SIMBL doesn't declare whether its event handlers are thread-safe.

You can find an explanation for this issue here:

This is a dopey cosmetic issue -- the warning is 100% spurious.

The event handler used in Snow Leopard is correctly labeled as thread-unsafe. The problem is that this warning is about the event used for Leopard - which is completely unaware of thread issues. I can't figure out how to get it to be backward compatible and stop complaining, so I'll let it complain.

Based on my understanding of the source code, you can try editing the Info.plist in the SIMBL bundle and remove the following from it:


It's the Leopard-specific event handler (leop).

  • Ah, thanks for the link! But (and I forgot to mention that) I also want to get rid of these messages. :) – Albert Aug 27 '11 at 15:04
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    Uninstall SIMBL like the rest of us did. Otherwise, live with the pain, because you can't turn off those messages. – peelman Aug 27 '11 at 15:16
  • I need SIMBL so that is not an option. SIMBL is open source, so there must be a way. – Albert Aug 27 '11 at 15:18
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    I also forked it on GitHub and here is a patch. – Albert Aug 27 '11 at 15:59
  • Where is the Info.plist file found? Also I'm confused from your comments as to wether or not editing the plist file will stop the errors from showing up in the console... – cwd Jan 18 '12 at 20:45

Thanks for all the info.

I went to the developer's website and updated SIMBL to the latest, and all is good now http://www.culater.net/software/SIMBL/SIMBL.php

The latest SIMBL installer also contains an "uninstall SIMBL" app, should the need arise.

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