When QuickBooks Multi-User Mode not working, it can disrupt business operations. This issue typically arises due to network configuration problems, incorrect hosting settings, or firewall restrictions. First, ensure that the QuickBooks Database Server Manager is installed and running on your server. Check that the hosting is enabled on the server but disabled on the workstations. Next, verify that the company file is stored in a shared folder with appropriate permissions. Adjust your firewall settings to allow QuickBooks-related processes and ports, and make sure your antivirus software isn't blocking access. Also, ensure that all users are running the same version of QuickBooks. If the problem persists, use the QuickBooks File Doctor tool to diagnose and fix network issues. By following these steps, you can resolve multi-user mode issues and maintain seamless operations in QuickBooks.