Are you sure it is gone or is just the shortcut not showing?  Check your programs or application file (depending on pc or mac).

Personally, I prefer not using the app at all.  I find it buggy, especially the Mac one.   So I just log in via the web browser.

Resolution for 'application file issue: 'how do i troubleshoot windows app?' available: Yes.

The application file 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 application file issue yourself by looking for a resolution described in the article. If it is a complex application file issue or you are unable to solve the issue, you may contact us by clicking here or by using other application file support options.

For more information about resolving issues related to application file in Quickbooks/QBO or to get support for the issue 'how do i troubleshoot windows app?', click the link below: