left navigation bar is blank.

Thank you for informing us of your concern, martin86. Allow me to share some troubleshooting steps that can aid you in resolving the unexpected behavior in the left navigation of QuickBooks.

The outdated stored cache can affect the performance of the program. I recommend accessing your account using an incognito window. This way, we can determine whether this is a browser cache-related issue. 

Incognito mode helps us verify the issue since this doesn't save any files. Here are the keyboard shortcuts:

• Safari: Command + Shift + N
• Google Chrome: CTRL + Shift + N
• Mozilla Firefox or Microsoft Edge: CTRL + Shift + N

If all the options in the left navigation menu are now showing, clear the browser's cache. Doing so deletes all the data from your browser and optimizes its performance. You may also use other supported browsers as an alternative.

I'll also be sharing an article that will guide you in customizing your navigation menu to best suit your workflows and habits: Understand the navigation menu in QuickBooks Online.

Please know I'm only a click away if you need further help with your navigation in QuickBooks. I'm always here to guide you over. Keep safe.