One of the gotchas you may encounter when migrating mailboxes to Exchange Online is none registered Accepted Domains in Exchange Online. For example you may encounter the below error;
ERROR: Migration Permanent Exception: You can’t use the domain because it’s not an accepted domain for your organization –> You can’t use the domain because it’s not an accepted domain for your organization.
This maybe due to an email alias on a particular mailbox or all your organisation mailboxes due to an Email Address Policy. When migration to Exchange Online on you need to register all your accepted domains and remove any that may cause you the above issue.
In my case, I had domain.com registered with EXO but not extension.domain.com, as the alias was a legacy address you could be removed from the mailbox either using the Exchange Management Console or my favourite utility PowerShell.
Please ensure that Azure Active Directory has synchronize this change to your mailbox
When working with Exchange there may be a requirement to create a PowerShell script using PowerShell ISE. Even if you run ISE on a Exchange Server you are unable to get the Exchange cmdlet in ISE, so the workaround for this is to use the following command;
If you are trying to add the Exchange cmdlets to your client machine you will need to Install the Exchange Management Tools from the Exchange installation media
The command to import the Exchange modules is different for each version – please use the appropriate command below:
So do you know if you have duplicate recipient alias within your Exchange organisation? Heres a quick script that will look at your Exchange Environment and download all recipient address into a handy csv file you to play with.
Do you have a requirement to understand how many Distribution Lists exist within your Exchange organization or need to understand if they actually being utilized? Well, this is something I have come across recently while working for the customer. They have a mass of distribution lists across their organization which they are trying to tidy up before migrating to Office 365. The organisation I was working for had over 100,000 distributions list but the state of them was unknown so what challenges did I face?
The challenges faced
Unknown the number of DLs that had 0 members
Unknown the number of DLs that had 0 managers
Unknown the number of DLs that had invalid characters
The solution… PowerShell
So the following script was created to obtain the all the attributes listed before, this enable to put together a business case for which distribution lists should be deleted and which should be migrated.
When working with large organisations that have multiple SMTP Domains, you may run into a requirement where you need to know. How many mailboxes have blogabout.cloud as their PrimarySMTPAddress or have blogabout.cloud listed as their EmailAddress.
Using the below PowerShell snippet you can find out exactly