Is it possible to migrate Exchange 2003 content from an old domain "sub.olddomain.local" to Exchange 2010 in a new domain "domain.local" without losing information, if I want to do a clean install of the new domain without co-existence and cross-forest/site-migration? The reason is, that the old domain is faulty, because my predecessor screwed up the active directory.
It's a small company with only 15 users, so it wouldn't be too much work to create the new users, groups and permissions, but I am a little bit worried about the Exchange part.
I'm planing to export mails, calendars and contacts to PST files (is there an advantage of using EXMERGE instead of an Outlook client to do the export?) on the old Exchange 2003 server and import them to the new users in the new domain (Exchange 2010). The users will keep the same external email addresses as before, but I suspect that this is not enough for exchange to regognize that it is the same user.
How will this affect existing mails, calendar items, address items and public folders? What additonal steps are necessary to allow users to work seamlessly with the old items?
What will happen to appointments? Will exchange be able to allocate the new users to the old user items as long as the email adress of the new user is the same or how do I reconnect the old and new accounts in a way that participants of an appointment are correctly identified and handled?
I read that users won't be able to reply to old emails. How can I fix this?