QuickBooks is an essential accounting software used by businesses to manage finances, transactions, and payroll efficiently. However, users sometimes encounter errors that disrupt workflow. One such error is QuickBooks Error Code H303, which occurs when QuickBooks cannot access a company file located on another computer due to improper hosting configuration or network issues.
In this detailed guide, we’ll explore the causes, symptoms, troubleshooting steps, and preventive measures to fix QuickBooks Error H303 and ensure smooth operation.
What is QuickBooks Error Code H303?
QuickBooks Error Code H303 is part of the H series errors (H101, H202, H303, H505), which generally indicate multi-user mode issues. The error signifies that the computer trying to access the QuickBooks company file needs additional configuration to connect to the server hosting the file.

This error typically occurs when QuickBooks cannot establish a connection to the host computer due to incorrect settings or firewall restrictions.
Symptoms of QuickBooks Error H303
If you’re facing QuickBooks Error H303, you may experience the following symptoms:
- QuickBooks fails to open the company file in multi-user mode.
- The system becomes sluggish when trying to access QuickBooks.
- Error message “QuickBooks Error Code H303” appears on the screen.
- QuickBooks crashes or freezes frequently.
- Inability to switch from single-user mode to multi-user mode.
Causes of QuickBooks Error Code H303
Several factors can contribute to QuickBooks Error H303, including:
- Incorrect Hosting Configuration – If hosting settings are incorrect, QuickBooks may not allow multiple users to access the file.
- Firewall Restrictions – A firewall may block communication between QuickBooks and the host computer.
- Damaged .ND File – The Network Data (.ND) file helps QuickBooks locate the company file on a network. If corrupted, it can lead to error H303.
- Issues with QuickBooks Database Server Manager – If the Database Server Manager is not running properly, QuickBooks cannot connect to the server.
- Network Connection Issues – A weak or unstable network connection can interrupt access to the QuickBooks file.
- Multiple QuickBooks Processes Running – If multiple instances of QuickBooks are running on the network, it can cause conflicts.
How to Fix QuickBooks Error Code H303
To resolve QuickBooks Error H303, follow these step-by-step solutions:
Solution1: Verify Hosting Settings on Workstations
- Open QuickBooks on all computers experiencing the error.
- Go to File > Utilities.
- If you see Stop Hosting Multi-User Access, select it. If you see Host Multi-User Access, leave it as is.
- Restart QuickBooks and check if the error persists.

Solution2: Use QuickBooks Database Server Manager
- Press Windows + R and type services.msc, then hit Enter.
- Find QuickBooksDBXX (XX represents your QuickBooks version).
- Right-click and select Restart.
- Open QuickBooks and check if the error is resolved.
Solution3: Rename .ND and .TLG Files
- Navigate to the folder where your QuickBooks company file is stored.
- Locate files with .ND and .TLG extensions.
- Rename them by adding .OLD at the end (e.g., CompanyFile.qbw.nd.old).
- Restart QuickBooks and see if the issue persists.
Solution4: Configure Windows Firewall Settings
- Open Control Panel and go to Windows Defender Firewall.
- Click Allow an app or feature through Windows Firewall.
- Ensure QuickBooks and QuickBooks Database Server Manager are allowed.
- Restart the system and try opening QuickBooks again.
Solution5: Check Network Connectivity
- Press Windows + R, type CMD, and hit Enter.
- Type ping [Server Name] and press Enter.
- If the response shows packet loss, check your network settings.
- Restart your router and reconnect the network.
Solution6: Run QuickBooks File Doctor Tool
- Download and install QuickBooks Tool Hub from Intuit’s official website.
- Open the Tool Hub and select Company File Issues.
- Click Run QuickBooks File Doctor.
- Follow on-screen instructions to repair the company file.

Preventive Measures to Avoid QuickBooks Error H303
To prevent encountering Error H303 in the future, consider implementing these best practices:
- Regularly Update QuickBooks – Keeping QuickBooks updated ensures compatibility with your network and security patches.
- Use a Stable Network Connection – Ensure a strong and stable network to prevent connectivity issues.
- Configure Firewall and Security Settings Properly – Allow QuickBooks through the firewall and security programs.
- Keep QuickBooks Database Server Manager Running – This tool ensures proper multi-user access to company files.
- Avoid Using QuickBooks on Multiple Workstations Simultaneously – Ensure that only one workstation is hosting the file.
- Perform Regular Backups – Create backups frequently to prevent data loss in case of file corruption.
Conclusion
QuickBooks Error Code H303 can be a significant obstacle when working in multi-user mode, but following the troubleshooting steps above can help you resolve the issue efficiently. Identifying the root cause, fixing network settings, and ensuring proper firewall configurations are key to preventing this error in the future.
By maintaining updated software, stable network connectivity, and correct hosting settings, you can prevent disruptions and ensure smooth QuickBooks operations.
FAQs
QuickBooks Error H303 occurs when a workstation fails to access the company file stored on another system due to improper hosting settings, firewall restrictions, or network issues.
Yes, you can follow troubleshooting steps like verifying hosting settings, restarting the Database Server Manager, and running the QuickBooks File Doctor to fix the error.
You can check your firewall settings in Control Panel > Windows Defender Firewall > Allowed Apps, ensuring that QuickBooks is listed as an allowed program.
No, renaming these files will not delete your data. QuickBooks will create new .ND and .TLG files when you open the company file.
To prevent this error, ensure that hosting settings are configured correctly, use a stable network connection, allow QuickBooks through the firewall, and keep QuickBooks updated.