Does anyone else have problems with the QB app after last update? It will not load and shows a green diagonal line in front of the word 'dashboard' on the tab

Welcome to the Community, @vonnie.

Thanks for reaching out to us. I got the steps you need to fix this unusual behavior in your QuickBooks Online app. 

When the application is not fully functional, performing the recommended basic troubleshooting steps will resolve the issue. 

First, clear the apps cache files. Doing so helps in fixing any sorts of errors in the system. Here’s how to do that:
1.    Click the Help menu at the top of the screen.
2.    Select the Rest App Data option on the drop-down selection.

If you get the same result, uninstall and reinstall the QuickBooks Online app. This is to ensure you get the most recent version of the application.  

I recommend the following article as it contains additional insight on the app and troubleshooting: QuickBooks App for Windows and Mac: General Support.

Should you be unable to load QuickBooks after following the steps, I suggest using a web browser in the meantime as a workaround.

This should get you back up and running. Please know I’m only a post away if you need further assistance. Thanks for dropping by and take care!