Hi there @KatnissBookkeeper, thanks for reaching out about this. I'm happy to help clarify.

The feature to open and switch between multiple companies from one window is still available in the QuickBooks Online app. I've just tested this myself, including deleting and reinstalling the app to ensure I was using the current version, and I was able to open and manage different companies as expected.

Since you've already tried some of the key troubleshooting steps like closing and reopening the app, and even deleting and reinstalling it, the issue might be more specific to your account or system. I recommend clicking the Help icon in the top righthand corner of your QuickBooks Online account, where you can connect with an expert who can troubleshoot further and escalate to our engineers if needed.