Why is you online platform even over a 150mb connection on one of the fastest Mac systems known to man so slow and clunky, it’s always crashing my browser?
I'm here to help you resolve this unexpected behavior when using the app, @maxbeckett.
There are several possible reasons why your QuickBooks Online desktop app. Let's start by clearing the Window App's Cache one more time for good measure. Here's how:
Click Help on the navigation bar at the top.
Select Reset App Data.
Allow a moment for the process to complete, and then close the app.
Be sure to right-click the app and Run as Administrator when re-opening.
If you get the same result, you can uninstall and reinstall the app to start a clean slate. After uninstalling, you'll want to get the latest version of the app from this page: https://quickbooks.intuit.com/online/apps/.
Also, you can always scan through these articles to learn more about the best practices that you can perform if you experience unexpected behavior: