There's a memory leak in LW 4.10 for Mac OSX. As soon as you do a search, the VM memory increases & doesn't stop. My suggestion would be that in the meantime you aim for one of Jum's builds that does not include the Spam filter. Look at his nightly builds as he normally includes a no. of versions. Choose one of the earlier ones.

My LW 4.10 runs for 1 hr if I do a search & then crashes. However, as OAH said, he tried the version without the spam filter & it seems to work ok for him. The alternative is to step back a version until LW releases a bug fix.