Cannot add users in quickbooks desktop

I greatly appreciate your efforts in conducting initial troubleshooting, @wcarter64. I can offer additional troubleshooting steps to resolve this issue so you can add a new user to QuickBooks Desktop (QBDT).

First, ensure you have updated your QuickBooks Desktop to the latest release so you have the latest security updates and fixes.

If the issue persists after updating, you can verify and rebuild data to help resolve common cases in your company file that prevent you from adding new users in QBDT.

Here's how to verify your company data:

1. Proceed to the Window tab, then Close All. 
2. Click on File and select Utilities.
3. Choose Verify Data. Hit OK. If you see:

• QuickBooks detected no problems with your data—your data is clean, and you don’t need to do anything.
• An error message—search for it on our QuickBooks Desktop support site for the steps to fix it.
• Your data has lost integrity—Data damage was found in the file. Rebuild your data to fix it.

Once done, you can follow these steps to rebuild your company data:

1. Go to the File menu, then choose Utilities.
2. Select Rebuild Data. QuickBooks will prompt you to do a backup before rebuilding your company file. Pick OK.
3. Save your backup, and OK. 
4. When the Rebuild has completed message appears, hit OK. 

After completing these steps, you can add a new user to QuickBooks Desktop again.

For future reference, you can also consider visiting these articles to learn how to modify the primary admin user in QuickBooks Desktop:

• Request to be the primary admin or contact.
• Transfer the primary admin role in QuickBooks Desktop.

If there's anything else you need help with when adding your new user to QuickBooks Desktop, please let me know by leaving a comment below. I'm just a few clicks away to help you again. Keep safe, and have a great day!

@wcarter64 

Run Verify/Rebuild Data utility. Did you encounter any error message?