I believe this is due to Mac El Capitan release. ┬áThis started happening to me as well after the upgrade. ┬áHere’s a workaround I have. You have to check the “Save in Drafts Folder” . Then it shows it in Mac Mail with the attachment, and you can send it. […]

Resolution for 'bug fixed issue: 'The sales receipt is not being attached to the email to customer.' available: Yes.

The bug fixed issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the bug fixed issue yourself by looking for a resolution described in the article. If it is a complex bug fixed issue or you are unable to solve the issue, you may contact us by clicking here or by using other bug fixed support options.

For more information about resolving issues related to bug fixed in Quickbooks/QBO or to get support for the issue 'The sales receipt is not being attached to the email to customer.', click the link below: