Exchange 2007 SP1 Update Rollup 4 Nightmare

I was one of the unfortunate who happened to install the update Tuesday night. I followed Scott Roberts’ instructions for fixing the EWS web.config, but I had an additional anomaly. Throughout the entire web.config were randomly scattered NULL characters which had replaced valid characters. So for some people, a find and replace on %ExchangeInstallDir% might not completely solve the issue. Try opening the web.config up in a better text editor that is capable of displaying non-text ASCII characters. I used Notepad++ for this. You will still have to find and fix the NULL characters by hand. See the MS Exchange team blog entry for more info.

http://msexchangeteam.com/archive/2008/09/11/449787.aspx