When QuickBooks multi user mode not working is an issue, it can hinder collaborative access to the company file. Experiencing issues with QuickBooks Multi-User Mode can disrupt workflow and productivity. To troubleshoot, start by ensuring the server hosting your QuickBooks company file is set to Multi-User Mode by navigating to File > Utilities > Host Multi-User Access. Next, confirm that each user has the necessary permissions to access the company file. Firewall and antivirus settings can also cause problems, so configure them to allow QuickBooks processes such as QBW32.exe and QBUpdate.exe. Additionally, make sure the QuickBooks Database Server Manager is installed and running on your server. You can open it from the Start menu and scan your company file location. Finally, check your network connections to ensure all computers are on the same network. Following these steps should help resolve Multi-User Mode issues and get your team back on track.