Description
The error "attachment data exceeded maximum size" in Salesforce occurs when the size of an attachment exceeds the maximum allowed size. This can happen when sending an email, importing content, or attaching a file to a record.
Possible causes
The attachment size is too large
The batch size is too large
The organization's file storage limit has been reached
Possible solutions
Increase the maximum attachment size limit
Reduce the size of the attachment
Reduce the size of the import file
Use Content or Salesforce Files for documents larger than 25 MB
Attachment size limits:
Inbound email attachments: The maximum size is 35 MB, including the email body, headers, and attachments.
Notes and Attachments in Salesforce Classic: The default limit is 25 MB, but Salesforce Support can increase it up to 65 MB
Notes and Attachments in Salesforce Lightning: The limit is 2 GB
Email attachments in Salesforce Classic: The total file size for multiple attachments cannot exceed 18 MB
Email attachments in Salesforce Lightning: The total file size for multiple attachments cannot exceed 25 MB