Performing the actual migration is often a moment to cross your fingers … and of course you will receive some errors when you start moving the first mailboxes.
Property Expression isn’t valid
Luckely, this one can pretty easy be fixed.
Follow the following steps:
- Start the Exchange Management Console
- Go to Recipient Configuration, Mailbox and find the affected user
- Go to the Properties Page
- Check the Alias field for invalid characters and remove them.
- Select Apply
- You will get a warning that the user will be upgraded to the current version of Exchange, Select OK
- Select OK
Now you should be able to move the mailbox to the new mailbox datastore.