Check for Invalid Aliases in Exchange and AD Before Migrating to Office 365

As part of the process to migrate from Exchange to Office 365, it is very important to check for invalid characters (see list below) in a mailbox alias. Essentially, we can have two options.

1) IdFix DirSync Error Remediation Tool

IdFix is used to perform discovery and remediation of identity objects and their attributes in an on-premises Active Directory environment in preparation for migration to Office 365. IdFix is intended for the Active Directory administrators responsible for directory synchronization with the Office 365 service.


2a) Run the following commands from the Exchange Management Shell (EMS)…

Get-Mailbox -ResultSize Unlimited | findstr "Warning"
Get-Contact -ResultSize Unlimited | findstr "Warning"
Get-DistributionGroup -ResultSize Unlimited | findstr "Warning"
Get-DynamicDistributionGroup -ResultSize Unlimited | findstr "Warning"
Get-PublicFolder -ResultSize Unlimited -Recurse | findstr "Warning"


2b) Perform a manual cleanup of the aliases with invalid characters; or use Fix-Alias.ps1 as an automated way to replace the invalid characters.


Either way it is decided to fix the aliases, it has to be done before the affected users will synchronize with O365 successfully.





List of characters not permitted in Azure AD (Office 365)…

This behavior occurs because certain special characters aren’t permitted in user names that you create in the Office 365. These special characters include but aren’t limited to the following:

  • Tilde (~)
  • Exclamation point (!)
  • At sign (@)
  • Number sign (#)
  • Dollar sign ($)
  • Percent (%)
  • Circumflex (^)
  • Ampersand (&)
  • Asterisk (*)
  • Parentheses (( ))
  • Hyphen (-)
  • Plus sign (+)
  • Equal sign (=)
  • Brackets ([ ])
  • Braces ({ })
  • Backslash (\)
  • Slash mark (/)
  • Pipe (|)
  • Semicolon (;)
  • Colon (:)
  • Quotation marks (“)
  • Angle brackets (< >)
  • Question mark (?)
  • Comma (,)

However, the following exceptions apply:

  • A period (.) or a hyphen (-) is permitted anywhere in the user name, except at the beginning or end of the name.
  • An underscore (_) is permitted anywhere in the user name. This includes at the beginning or end of the name.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s