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Today Firefox started crashing whenever I'm trying to open the preferences editor, and also often during normal navigation. If I start Firefox from a terminal, when it crashes it returns the message: Attempting to load the system libmoon.

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up vote 3 down vote accepted

It seems you've run into an instance of this bug:

The workaround for now seems to be removing the moonlight browser plugin:

apt-get purge moonlight-plugin-core moonlight-plugin-mozilla
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This is a common issue caused by Moonlight plugin. Uninstall moonlight-plugin-mozilla to solve your problem.

sudo apt-get purge moonlight-plugin-mozilla

If you still need Moonlight, then you could try the 3.0 preview version from:

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