Hi @Citleial
Welcome to our forum!
For better research, please provide more details about this case:
What is your account type (POP/IMAP/Exchange)?
What is the client version? Please upgrade to the latest version.
Can you search for missing messages in the search box?
Try these possible resolution steps:
Please log in to the web version of your account to check if the email is gone.
If the problem only occurs on the desktop client, try creating a new configuration file to check if that helps.
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