Good afternoon, Deadwood Al.

Thanks for bringing your question forward here in the Community. I want to make sure your customers are able to view attachments when sent from your QuickBooks Desktop account.

Based off of the description, this sounds like a potentially broken invoice template. To rule this issue out, I recommend creating a new template to test and see if the same results occur with a new one. Here's how to get this done:

1. In the File menu and select Switch to Single-User Mode.

2. Go to the Edit menu and choose Preferences.

3. Select the Send forms menu and then the Company Preferences tab.

4. From the Delivery Method Default drop-down menu, select Email.

5. In the Email Templates drop-down menu, select a transaction type. You can create multiple templates for each transaction type transaction listed.

6. Select Add Template.

7. Give your template a name.

8. Customize the subject line and body.

9. You can select Insert Field to put a dynamic data field in your email. These use real data from the form, like the customer name or due date, to fill out the field.

10. When you're done customizing, select Save. After you close the template, select OK in the Company Preferences tab to save your changes.

The following article provides additional info about creating custom email templates in QuickBooks Desktop.

Once you've completed these steps, send an invoice with an attachment to one of your customers that has run into the issue and see if they're able to view the PDF. Please don't hesitate to reach back out in the comments below if you have any other questions or concerns. I'll be here to lend a hand.