The case of the mailbox validation error

Today I noticed a strange warning when opening a mailbox:

WARNING: The object domain.local/Productie/Users/SomeOU/LoaderA0001 has been corrupted, and it's in an inconsistent state. The following validation errors happened:
WARNING: Property expression "LoaderA0001" isn't valid. Valid values are: Strings that includes '@', where '@' cannot be the last character

 

It complains about the @ sign being an invalid character, but it’s not in there!

I opened PowerShell and used the Validate method off the Mailbox object and this gave a more precise error:

Constraint         : Microsoft.Exchange.Data.RegexConstraint
InvalidData        : LoaderA0001
PropertyDefinition : UserPrincipalName (System.String)
Description        : Property expression "LoaderA0001" isn't valid. Valid values are: Strings that includes '@', where '@' cannot be the last character
PropertyName       : UserPrincipalName

 

So it appeared to be a problem with the userPrincipalName attribute, I first changed it through the Exchange Management Shell but I got the same error there.

Then I opened the object with ADSI Edit and cleared the value of userPrincipalName:

image

Then I set the correct value using the Exchange Management Shell and that made everybody happy again!

Was once an enthusiastic PepperByte employee but is now working elsewhere. His blogs are still valuable to us and we hope to you too.