Hi,I have set up an internal sharepoint server with this name:\\montanaI created a public domain and it is:http:\\outside.domain.comI have tried creating the alternate mappings and they seem to wrk. My problem is that when I create a calendar on any of the sites and sync to outlook, it works, but when I create something locally on outlook and send/receive it crashes. I have tried it with both 2007 and 2010 betas (outlook).If I remove the alternate access mappings, and interally visit http://montana, the calendar sync works fine and outlook will not crash.My assumption therefore is that I am jacking the alternate access mappings. Or MS Outlook hates me. And since I have no sacrifices for the outlook gods I really need some help :)Thanks again,-Jason

Hi Jason,Please ensure the following Assumptions correct and post back?1. AAM Setiings for http://outside.domain.com2. You have not extended http://Montana to the extranet3. You are using NTLM authentication4. IIS WebSite HostHeaders for http://Montana and http://outside.domain.com exist5. IE Security Settings you have added http://outside.domain.com to your Intranet ZoneAlso, what version of SharePoint 2007 > Go to CA > Site Settings and the Number i the upper middle should be simething like 12.0.0.6504Ivan Sanders My LinkedIn Profile, My Blog, @iasanders.