Hello there, Cybertranz.

Let's perform some steps to resolve this and gets you able to attach pdf to invoice. Before doing so, may I know the exact error that you've encountered? Any additional information is appreciated.

Meanwhile, you can run a clean install of QuickBooks to resolve this. 

Here are the steps:

• Make sure a clean install is right for you.
• Gather info and back up your data.
• Uninstall QuickBooks Desktop.
• Use the QuickBooks Clean Install Tool

• Reinstall QuickBooks Desktop

Each of these steps have sub-steps. To see them, kindly see this article: Clean Install QuickBooks Desktop.

If the same thing happens, you may be having an issue with your company file. You can run a rebuild data and verify data utilities to resolve data damage. 

Let me know how these steps work for you. Just leave a reply below.