Thank you. We were also able to fix this issue this way. We had to close out of Quickbooks to try this again after changing the "Run as Administrator" box.

We would restate the steps as

1. Try to email the invoice. Once you get the error message -

2. Open Task Manager (click on the Windows Start Menu and type Task to find it).

3. Details tab. Look for qbmapi64. Left click to select it. Right click and select Properties.

4. In Properties click on the Compatibility tab. Check the "Run as Administrator" box. Apply. OK.

5. Close out of the QB error and dialog boxes and out of QB itself.

6. Open QB again and email the invoice.