Salesforce Email Attachments Sent as HTML File Links

The following sections describe why attachments appear as HTML file links for each Salesforce email type, and what recipients can do to access the attached files.

HTML Links in Mass Emails (Salesforce Classic Only)

When using the Mass Email feature in Salesforce Classic, it is possible to include file attachments in emails. However, if an email template includes an attachment, all attachments sent via that template will arrive as .html file links — this is expected behavior and cannot be changed.
To access the attachment, the email recipient clicks the .html link, which opens the file in a new browser window. The recipient can then choose to save the file locally.

HTML links in List Emails (Lightning Experience only)

When using the List Email feature in Salesforce Lightning Experience, attachments will always be sent as .html file links. This is by design and cannot be overridden.
To access the attachment, the email recipient clicks the .html link, which opens the file in a new browser window. The recipient can then save the file locally.

HTML links in Single Emails

• When sending a single email using the Send an Email button (Salesforce Classic) or the Email publisher action (Salesforce Lightning Experience), attachments may be sent as .html links if the Email Attachment Settings are configured to send attachments as links 'Email attachment' settings.
• When recipients click the .html attachment link, the file opens or downloads natively in their web browser. Important: Salesforce stores these attachment link files for 30 days after the email is sent. If a recipient attempts to open the link after 30 days, they will see a message stating the file is no longer available and will need to contact the sender to request the file be re-sent.