SymptomsStatistics for Mail accounts is red marked and displays incorrect total size at Plesk Control Panel -> Domains -> yourdomain.com -> Report .
CauseWhen Plesk Control Panel is assigned to centralized mail through Plesk Expand all mail accounts from Plesk are migrated to centralized mail server, it processes mail service in future.
Mailboxes are not removed from Plesk Control Panel, their size is displayed in domain statistics and may be at variance with real size of mail accounts in centralized mail.
Currently there is no way to display actual size of mail account in Parallels Plesk Panel. Correct statistics is shown on Centralized Mail server.
ResolutionPlesk Expand version 1.x and 2.x cannot cause actual mail statistics from centralized mail server be displayed in Plesk Control Panel.
Actual statistics of mail accounts is displayed in centralized mail server only.
AdditionalInformationBy default content of mail accounts is not migrated from Plesk Control Panel to centralized mail server during assigning, check box Migrate mail should be marked to migrate mailing lists and mailboxes.
Content of mail accounts cannot be migrated to Windows-based central mail server or from Windows-based Plesk Contorl Panel.
Please refer to Expand administrator's guide for more details:
Assigning a Plesk Server to the Central Mail Server