Exchange 2010: Mailbox role installation failed or partially configured or setup failed while configuring it

The issue may occur due to the presence of the Action or Watermark registry values on this registry, the presence of the Action or Watermark registry values on this registry branch indicates that either there was a previously unsuccessful installation of the Mailbox server, or that the Mailbox server installation was in progress when the Exchange Server Analyzer was doing its analysis.

So to address the issue, we can first turn to the Exchange setup logs to clarify if installation completed successfully. We can locate the setup logs at c:\ExchangeSetupLogs.

If we verified that the installation of Mailbox server is successful, we can delete Watermark or Action keys in regedit "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v14\MailboxRole" to resolve this issue.