Since you have tried to uninstall and reinstall and I am going to assume you also cleared the cache and cookies in your browser, you can try an app reset. Steps:

1. Quit the app if it is running.

2.Holding SHIFT key pressed, double click on QuickBooks desktop shortcut. (Keep the SHIFT […]

Resolution for 'app reset issue: 'Quickbooks Online Windows app update broke the app. Uninstalled and reinstalled four times. Still will not work.' available: Yes.

The app reset issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the app reset issue yourself by looking for a resolution described in the article. If it is a complex app reset issue or you are unable to solve the issue, you may contact us by clicking here or by using other app reset support options.

For more information about resolving issues related to app reset in Quickbooks/QBO or to get support for the issue 'Quickbooks Online Windows app update broke the app. Uninstalled and reinstalled four times. Still will not work.', click the link below: