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I just downloaded Thunderbird 3.0 on my Macbook Pro running Leopard, and installed it in /Applications. When I attempt to start it, the icon opens on the Dock as normal, but I get the following dialog.

Close Thunderbird

I don't have a ~/Library/Application Support/Thunderbird directory at all, let alone a .parentlock file. While I didn't expect it to help, I did reboot my system. And sign out and back in. And close all programs besides Thunderbird.

Earlier versions of Thunderbird have worked just fine.

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Thunderbird can create Profiles (and subsequently .parentlock files) at ~/Library/Application Support/Thunderbird/ and ~/Library/Thunderbird/. The newer versions are supposed to put it in Application Support but I've seen instances where that is not the case.

Alternatively running find ~ -name ".parentlock" from the command line may help find the file (as the GUI/Spotlight won't show the file by default).

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Right. Those directories don't exist because Thunderbird hasn't actually started yet. – jtimberman Dec 10 '09 at 0:14
So find ~ -name ".parentlock" revealed no .parentlock folders anywhere in your home folder? – Chealion Dec 10 '09 at 4:52
No. But it started just fine the other day, though I'm sticking with – jtimberman Dec 18 '09 at 16:57

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