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QuickBooks Connection Diagnostic Tool

QuickBooks Connection Diagnostic Tool is part of the QuickBooks tool hub. The main purpose of the tool is to scan for company file errors and network issues related to the accounting software. QuickBooks error H202 H303 and H404 can be resolved using the QuickBooks connection Diagnostic tool. Network issues can arise because of security software such as antivirus and firewall.  Connection related errors are also common when users host their company file on a separate server.

As QuickBooks tool hub can be downloaded and installed for free, users don’t have to pay any extra amount to use the QuickBooks Connection Diagnostic Tool. So you can simply install the utility and use the program to resolve common network issues. Further you can use the tool hub to troubleshoot and fix various errors related to the program file, the company file, and installation of the software.

In this post, you will learn how to use QuickBooks Diagnostic tool to fix network related errors.

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What is the QuickBooks connection Diagnostic tool used for?

QuickBooks Connection Diagnostic tool is a free program that can troubleshoot network and multi-user mode errors related to company files in QuickBooks desktop. It can help with errors including H202, H505 and 6000 series.

You can access this program from the QuickBooks tool hub, which is available for free from Intuit’s website. We have provided a download link for the same below.

QuickBooks Connection Diagnostic Tool can fix the following errors:

  • QuickBooks error H202
  • QuickBooks error H303
  • QuickBooks error H404
  • QuickBooks error H505
  • -6000 series error related to network
  • Multi-user mode error

How to use  QuickBooks Connection Diagnostic Tool to fix common network errors?

QuickBooks Connection Diagnostic tool is a user friendly program that helps you to understand the underlying reason of the error and resolve the error. Here are the steps to use this program to fix common network errors in QuickBooks desktop.

Step 1: Download and Install QuickBooks Tool Hub

Before you begin the installation of this program, you need to download the setup from Intuit’s website.

Click here to download the latest copy of QuickBooks tool hub.

Here are the steps to install QuickBooks tool hub on your system:

  1. Login to Windows with an admin account.
  2. Double click on the setup for QuickBooks Tool Hub.
  3. Agree to the terms and conditions.
  4. Follow the on-screen instructions to install QuickBooks tool hub on your system.
  5. Click on Finish once the installation is finished.

In most cases the installer creates a desktop icon for the tool hub so that users can quickly find and launch it from the desktop directly. However, if you can't find its icon on your desktop, then you can search the start menu, then launch the program.

Step 2 - Scan for common network issues

Now you have QuickBooks tool hub installed on your system, you can scan for common program, company and network issues. As it contains multiple programs to troubleshoot errors, you need to make sure that you are using the appropriate program to scan for network issues - in this case QuickBooks connection Diagnostic tool.

Here's how you can scan and fix network issues with QuickBooks Connection Diagnostic tool:

  1. Go to the start menu and click on QuickBooks tool hub.
  2. From the left panel, choose network issues.
  3. Click on  scan to launch the QuickBooks Connection Diagnostic tool.
  4. Wait for the scan to finish and the program to give you a message of success or failure in resolving the error.
  5. Restart your system once the tool is done scanning and fixing network issues in QuickBooks.
  6. After the scan, QuickBooks connection diagnostic tool will give you one of these two messages:
    • the identified errors have been resolved.
    • the identified errors weren’t resolved. 

In the latter case, the QuickBooks connection diagnostic tool will give you the necessary instructions to resolve the error.

Step 3 : Check your internet connection

While the QuickBooks Connection Diagnostic tool can fix a vast majority of network related errors, it cannot actually fix the internet issues caused because of security software or because of internet issues. So at this point you should definitely check your internet connection and contact your internet service provider if the connection isn't working properly. 

You may also have to check Firewall settings to ensure that QuickBooks desktop can actually access a company file that is stored on a different system or server. This is quite common for users who have hosted their company file on a separate server in order to activate multi-user mode in QuickBooks desktop.

Step 4: Check for company file errors

Even if you get a network related issue, the real problem may lie with the program files or the company files. In such cases, you need to scan for both types of errors and eliminate the underlying causes.

Here are the steps to scan this system for company file and program file errors:

  1. Go to the Start menu and launch QuickBooks Tool Hub.
  2. Click on program problems and wait for the program to scan files related to QuickBooks.
  3. After scanning for program problems, choose QuickBooks file doctor to scan for company file errors that may be presenting as network errors.
  4. Restart your system after you have successfully scanned for both the problems.

You only need to follow these steps if the previous solutions failed to fix the problem that you are facing. The scan for the company file and the program files does not take too long because the tool can efficiently go through the files and check for errors.


QuickBooks Connection Diagnostic tool works amazingly for resolving network errors in QuickBooks desktop. You can also check for other error types so that you can quickly and easily fix program and company file errors. Once you have resolved the error, we recommend that you create a backup copy of your company file and that you install the latest updates for QuickBooks Desktop on your system.


How do I download QuickBooks connection diagnostic tool?

Click here to download QuickBooks connection diagnostic tool. Once you install the setup, You will get access to QuickBooks tool hub, which contains the Diagnostic tool that you are looking for. You can download and install the program for free and then launch it to access the Diagnostic tool to scan for network errors.

How do I use the QuickBooks diagnostic tool?

To use the QuickBooks Diagnostic tool, you can install QuickBooks tool hub on your system . Through QuickBooks tool hub, you can access many tools that can help you resolve common errors that occur with this accounting software. Once you launch QuickBooks tool hub you can select Network Issues to launch the QuickBooks Connection Diagnostic tool.

How do I fix a lost connection in QuickBooks Desktop?

To fix a lost connection in QuickBooks desktop, you can rely on QuickBooks connection diagnostic tool, which can scan for network related errors and then fix those errors or give you the steps necessary to fix the underlying cause of the error.

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