Exchange 2010 – Modify a Database Size Limit

To change the database size limit for a specific database, do the following:

1. Dismount the database
2. Run regedit and go to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\\Private-Database-GUID
3. If the Database Size Limit in GB DWORD exists for the subkey, change its value to the desired size in gigabytes.
4. If the Database Size Limit in GB DWORD doesn’t exist for the subkey, create a new DWORD with that name, and then set its value to the desired size in gigabytes.
5. Mount the database.

You can get the GUID of a database by running the following command in the Exchange Management Shell:

Get-MailboxDatabase -Identity "" | Format-Table Name, GUID