Email-to-Case attachments don't get attached to the created case record

Email attachment visibility in Email-to-Case depends on the Salesforce experience and the administrator-configured settings. Review the relevant scenario below.

Salesforce Classic Behavior

In Salesforce Classic, attachments received on inbound emails processed by Email-to-Case are shown in the inbound email's Attachments related list. They are not shown in the Notes and Attachments (or Files) related list on the Case record itself.
To view the attachment, the user must navigate to the Emails related list on the Case, open the specific inbound email, and view the attachment from there.
If attachments are not appearing even in the email's Attachments related list, consider the following:

• A Salesforce trigger may be moving the attachment to a different location.
• A custom email service may be handling attachments differently.
• The org may have Email2Case Premium (a partner package) installed, which handles attachments separately.

Lightning Experience Behavior

In Lightning Experience, attachments are handled differently based on administrator settings:

• Default behavior: Attachments received on inbound emails are shown on the Email Message record's Attachments related list.
• If "Show Email Attachments in Case Attachments Related List" is enabled (Setup > Support Settings): Email attachments also appear in the Case Attachments related list. An email icon displays next to the file to indicate it came from an email. A Source column also appears in the list view.
• If "Save Email-to-Case Attachments as Salesforce Files" is enabled (Setup > Email-to-Case Settings): Attachments are stored as Salesforce Files and appear in the Files related list on the Case record.

Administrator Settings That Affect Attachment Visibility

Salesforce Administrators should ensure the following related lists are included on the Case Page Layout to avoid confusion for users:

• Attachments related list
• Files related list (if storing as Salesforce Files)
• Emails related list (to access Email Message records)