SymptomsMDaemon is not supported by Parallels Plesk Panel 10.x versions as a mail server. In case MDaemon is registered as a mail server in your Plesk Panel installation, you are advised to switch to MailEnable prior to performing an upgrade procedure to version 10.x.
ResolutionUse the following steps to reconfigure Plesk Panel to use MailEnable as the mail server before performing the upgrade procedure to version 10.x:
1. Backup existing mailboxes content with the following command:
C\>%plesk_cli%\pleskbackup.exe: --server -only-mail
2. Switch to MailEnable at Settings -> Server Components -> Mail Server -> Select "MailEnable"
3. Restore mailboxes content:
- Go to Home -> Server -> Backup Manager -> last backup
- Choose "Ask me what to do" in "If conflicts occur during the restoration".
- Click Restore button (even if it is grayed out), Next
- Choose "Use configuration and data from backup" in "Resolution policy", Next
Once the above steps are performed, it is safe to proceed with the Plesk Panel upgrade to version 10.x.