We migrated from one hosted Exchange provider to another and the biggest issue was internal bounces caused by Outlook using X500/X400 addresses. The X500 addresses are only valid for one particular Exchange system so unless you add the X500 address from the old system to the new one, every single user will at one point or another get internal bounces (because the old X500 address is no longer valid on the new system). The X500 addresses are stored within each message so if a user replies to an old message (one received before the migration), they will get a bounce. The "bad" X500 addresses then get put into the user's Autocomplete address list (NK2 file). If the old message they replied to also had external addresses, if one of the external people replies, they will get a bounce as well. The problem goes on and on and then affects both internal and external people.
This was by far the biggest problem during migration. And attending to this issue for so many users wasted many hours of IT staff's (and employees') time.
We never have had this issue with our Mac users who use Entourage or Outlook 2011 for Mac because those mail clients just store the universal SMTP addresses.
Why doesn't the Outlook team just retire the very problematic X500 addressing and use the more universal SMTP addresses?
This was by far the biggest problem during migration. And attending to this issue for so many users wasted many hours of IT staff's (and employees') time.
We never have had this issue with our Mac users who use Entourage or Outlook 2011 for Mac because those mail clients just store the universal SMTP addresses.
Why doesn't the Outlook team just retire the very problematic X500 addressing and use the more universal SMTP addresses?