lost some mail

lost some mail from inbox and sent folders.
i can see this mail only in Outlook Web App

Hi Mihail, what mail service are you using to synchronize your items with eM Client? Are you using an Exchange or an AirSync (Outlook.com) account? If so, please try to right click the inbox (and the sent folder) and select Properties > Repair and perform a folder repair on the specified folders.

Let the application to finish the folder synchronization and check if the issue persists.

Thank you,