OS 5.1 installed and Safari hasn't closed unexpectedly since. Maybe they fixed it. The release notes don't highlight this issue, but in the fine print they refer to several bug fixes. So far so good.

Quick, I was never particularly frustrated. It just didn't work. It wasn't a hardware issue, which would have clearly been warranty. It was a software conflict and Apple's next step was to remove all my applications. I wasn't interested in that. It was less trouble to live with it

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue