Hello there, Kiki2.

Thanks for keeping us posted. Allow me to join this thread and help you add class to your transactions.

If you're able to add class to certain transactions, you should be able to do it to other transactions. It's possible that there is a data damage within your company file. To fix this, let's verify and rebuild your QuickBooks software. This process is use to fix common data issues and unexpected behavior within the file.

Before we start, please secure a backup of your company.

To Verify:

1. Click File at the top menu.
2. Go to Utilities.
3. Select Verify.

To Rebuild:

1. Click File at the top menu.
2. Go to Utilities.
3. Select Rebuild.

Here's an article that'll serve as your step by step guide in resolving common data damage on your company file: Verify and Rebuild Data in QuickBooks Desktop.

That should do it. Stay in touch if there's anything else you need with adding classes in QuickBooks. It's always a delight to help.