This app keeps removing products from my selection when building estimates but has them in the product tab. I create them and they’re gone the next time

It's my pleasure to address your concern, citizensfirstfir.

May I know which app are you referring? Is this a third-party app or QuickBooks Online? If it's a third-party, did you encounter a specific error? If so, let me know. This way I can check and find accurate solution to the error.

If it's the QBO subscription, you'll want to perform some troubleshooting techniques, and ensure the problem isn't with your browser. The cause of this strange behavior is probably local internet cache files.

Start by using a private browser to log into QuickBooks. Here's how to do it:

• Command + Shift + N (Safari)
• Ctrl+ Shift + N (Google Chrome)
• Ctrl + Shift + P (Mozilla Firefox)

If it works, they need to delete the cache in their browser. Here's a link to an article that can assist them with the process: Clear cache and cookies to fix issues when using QuickBooks Online. Otherwise, you can try using other supported browsers to be through.

You'll want to  check out this article for more information about estimates: Set up and use estimates.

The Community is always open if you have other questions while working with estimates. I'll be around to help. Wishing you a great day ahead.