IntelliJ IDEA on Ubuntu: index corruption & rebuild

I'm trying out IntelliJ IDEA in earnest for the first time and have installed version 10.0.1 on 64 bit Ubuntu 10开发者_运维技巧.04 with Sun JDK 1.6.0_21.

Every time I start IDEA it tells me the indexes have become corrupted and need to be rebuilt. Any idea what might be causing this or how I might go about diagnosing the problem?

I haven't noticed this problem when I open the same project on the same version of IDEA on my MacBook Pro.

(I'm working on a Grails application with several plugins/modules, if that's of any relevance.)

Thanks.

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Check idea.log, most likely you do not shut down IDEA properly so that it's not able to save the index. File | Invalidate Caches may also help.