Create invoices missing customer summary information, just: "Loading..."

Welcome to the Community, @kimballkaos.

I can see the urgency of getting this resolved as soon as possible so you can get back to working order. To ensure that this gets sorted out, let's make sure that your QuickBooks Desktop (QBDT) is updated to the latest release to prevent possible data issues from happening. 

On the other hand, if your QBDT is up-to-date, we can perform some troubleshooting steps by verifying and rebuilding your company data. Let me guide you on how:

To verify data:
 

1. In your QBDT file, go to the Window menu, then select Close All.
2. Go to File. then select Utilities.
3. Select Verify Data. If you see:
   a. QuickBooks detected no problems with your data—your data is clean, and you don’t need to do anything else.
   b. An error message—search for it on our QuickBooks Desktop support site for how to fix it.
   c. Your data has lost integrity—Data damage was found in the file. Rebuild your data to fix it.

To rebuild data:
 

1. Go to File, Utilities, and then select Rebuild Data.
2. QuickBooks will ask you to make a backup before it rebuilds your company file. Select OK. A backup is required before you can rebuild.
3. Select where you want to save your backup, then OK. Don’t replace another backup file. Enter a new name in the File name and select Save.
4. Click OK when you get the message Rebuild has completed.
5. Go to File, select Utilities then select Verify Data again to check for additional damage. 
   a. If the verification finds more damage, you’ll need to fix it manually. Search for the error(s) in the qbwin.log on the QuickBooks Desktop support site for how to fix it.
   b. If your error can't be found, you can restore a recent backup. Go to File then select Open or Restore Company.

For detailed steps, kindly visit: Verify and Rebuild Data in QuickBooks Desktop.

Moreover, I'll also share this article that can serve as your reference if you want to learn how to use and personalize form templates in QuickBooks: Use and customize form templates.

Feel free to leave a reply if you require further assistance with your invoices in QBDT. The Community team always has your back. Have a good one.

None of that works. I forgot to mention that the data file itself is fine. I use the program on two different computers and the information shows up just fine on one but not the other. I've tried to uninstall and reinstall the program but to no avail, short of reformatting the whole computer (which is newer).

Thanks for following up with the Community, kimballkaos. I appreciate you performing DHeraV's recommended troubleshooting steps.
 

Since you've already confirmed you're up-to-date with your product's latest release and tried utilizing the Verify/Rebuild utilities, I'd recommend continuing to troubleshoot with our QuickBooks Tool Hub.
 

Here's how:

1. Close QuickBooks and download a copy of the utility's most recent version, then run it.
2. Follow along with your on-screen steps to complete installation and agree with our terms and conditions.
3. Once it's installed, double-click its icon to open the tool hub. If you can't find your app, perform a search in Windows for "QuickBooks Tool Hub" and select the program.
4. Access your Company File Issues tab and use the Quick Fix my file and QuickBooks File Doctor tools to troubleshoot your company file. In the event you need additional assistance, choose File Dr Help.

If your invoice creation screen continues to not load its Summary section under the Customer tab, you'll want to get in touch with our Customer Care team. They'll be able to pull up your account in a secure environment, conduct further research with you, and create an investigation ticket if necessary.
 

They can be reached while using QuickBooks:

1. In your top menu bar, go to Help, then QuickBooks Desktop Help.
   
   
    
2. Click Contact Us.
   
   
    
3. Enter a brief description of the issue in our Ask a question (or tell us what's wrong) field, then hit Continue.
   
   
    
4. Select We’ll contact you for a callback or Message Us to start an instant messaging session.

Be sure to review their support hours so you'll know when agents are available.
 

Please don't hesitate to send a reply if there's any questions. Have a lovely day!