em client data base malformed
how its resolve
If you have a recent backup, you can try a restore using Menu > File > Restore.
If you don’t have a backup, then there is generally no solution other than to delete the database and start again. You will lose any settings and local data, but if your account is setup as IMAP or Exchange, your messages will be resynced with the server after restart of eM Client and adding your email account.
To delete the database, close eM Client, and then delete or rename C:\Users_[username]_\AppData\Roaming\eM Client. You may have to show hidden items in Explorer to do that.