Cannot Create Mailbox In Exchange – Property Expression Isnt Valid

Written by Allen White on. Posted in Exchange 2007, Exchange 2010

When trying to add a Mailbox to a user in Exchange 2010 or Exchange 2007 you may come across the following error.To view a video of the solution head to the end of the article.

Property expression “Administrator” isn`t valid.Valid strings are.Strings that
includes `@` cannot be the last character

As seen here.

property expression isnt valid exchange mailbox

property expression isnt valid exchange mailbox


This is because in AD the users User Logon Name is ot assocaited with the FQDN for you domain, if you read the error it actially says it in a roundabout Microsoft way. To fix this do the following.

Go into Active Directory users and Computers the right click the user in question and select properties then Account.

Next to User Logon Name you will see a drop down menu. Select it and then select your domain.

Cannot attach mailbox to to user property expression

Cannot attach mailbox to to user property expression



Now when you try and add a mailbox to your user you will be able to complete the task successfully.

Allen White
Allen is a Consultant for ITPS in the North East of England and holds the following accreditations. MCSA, MCSE, MCTS, MCITP, CCA, CCSP, VCP 4,5 and HP ASE, AIS - Network Infrastructure.

ITPS provides strategic IT consultancy, implementation, data centre provision and unified communications, as well as support services and workspace and disaster recovery. If you require a consultation then please contact me via the contacts section or direct on 07931222991, add me on linkedin.


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