User cannot open an expense attachment and gets an error that the file no longer exists.
This can happen if you are using a storage service other than the default one that comes with Core (AWS) and the attachment no longer exists there. For example, if you are using OneDrive for storage and you delete an expense attachment there, you get the error when you try to open the attachment in Core. This is because that file no longer exists at the actual storage location. Check the Core Help for more details.