facing below error while creating new user mail box. Arvind

Did you successfully install the Exchange 2010 mailbox server (or only CAS/HUB server)? You need a cleanly installed 2010 mailbox server to create mailbox. http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/25fa3caf-6d92-4b83-aeb0-93f6c874ffd5/ If the mailbox server is up, then ensure that the databases are mounted properly. (the screen shot is not so clear, but I assume it is the same here). Praveen Balan |MCITP - Exchange Server 2010 | Exchange Dictionary(www.exchangedictionary.com)

And you can try this; http://www.johnmen.com/johnmen/it-proprietary/microsoft-exchange-server/exchange-2010-couldnt-find-a-valid-mailbox-database-when-creating-new-mailbox.html

Hi Arvind, Per the error information, that means it is failed to find a mailbox database. So, could you please confirm the above suggestions, and then post the update here. Or, you could run EXBPA and post the error information here, then we could narrow down the issue. Regards!Gavin TechNet Community Support

Hello, can you try specifying the database in the New-Mailbox command instead of allowing it to be automatically chosen. Thanks

create seperate databse adb try to create user on new database,

Hi Arvind, Any update for for your issue? Regards!Gavin TechNet Community Support

any updates ?

Hello any update , did you tried specifying the database in the New-Mailbox command instead of allowing it to be automatically chosen. Thanks

pls update ??