QuickBooks Integrator: Common QuickBooks Connection Errors

Troubleshooting QuickBooks connection errors.

Date Entered: 05/04/2012    Last Updated: 08/02/2016

The following are the most common QuickBooks connection errors.

Error 606 - Could Not Start QuickBooks.
Error 851 - The QuickBooks request processor was not found.

Below are some potential causes of the above errors, and how to resolve these issues.


1. QuickBooks is not running

The first time an application connects to QuickBooks, you must have QuickBooks running with the company file opened by an administrator for the company file. This will allow you to grant the application the permission it needs to connect to QuickBooks.

Note: If QuickBooks is not running you must specify a CompanyFile.


2. Full permissions have not been granted

Verify that you have granted the connecting application full permissions. To view a list of applications that have been granted access to QuickBooks, go to 'Edit->Preferences', 'Integrated Applications (Company preferences Tab)'.

If you were previously able to connect to the company file, but are now seeing an error, try removing your application from the list (highlight and click Remove), running it, and granting it permissions again.


3. Running on a 64-bit machine

The QuickBooks Integrator communicates directly with QuickBooks, and QuickBooks does not currently have native 64-bit support. This means that applications communicating with QuickBooks must be run in 32-bit mode when running on 64-bit architecture.

On 64-bit machines, you will need to use the Remote Connector for QuickBooks application provided with the installation to bridge the connection to QuickBooks via a 32-bit application. Alternatively, you could target x86 processors when compiling your application to create a 32-bit application. By default, Visual Studio targets 'Any' processor, you will need to change this to x86.


4. UAC and "Run as Administrator" Settings

QuickBooks requires that connecting applications be run from the same user account that QuickBooks is running from. Because of this, User Account Control (UAC) and "Run As Administrator" can cause issues, especially in development environments. If one of the applications is run with elevated permissions, the COM communication will fail, as Windows 7 will treat them as separate users.

Additionally, running a connecting application from an environment with elevated permissions (such as a debugger) can cause problems. If you run into connection issues while running your application from a debugger, try running the compiled executable.


5. Web Applications

Most Web applications will try to run as a different user account than the local user account running QuickBooks. This will cause the COM communication with QuickBooks to fail, as it requires both applications to be running on the same user account. You will need to either try Account Impersonation, hosting the web app from the local user, or the Remote Connector for QuickBooks application.

By default, ASP.NET does not use impersonation and instead executes all code using the same user account as the ASP.NET process, which is typically the ASPNET account. To use impersonation, add the following tag inside the system.web section of your web.config file:

<identity impersonate="true" userName="domain\username" password="password" />


6. Updated to a new version of QuickBooks

QuickBooks may leave behind old registry files when upgrading from one version to another. This can cause the QB Request processor to look in the wrong locations when trying to start QuickBooks.

In extreme cases, if you've upgraded from one version to the next, it may be necessary to wipe the machine and to re-install QuickBooks.


7. The QuickBooks SDK log file (qbsdklog.txt)

QuickBooks maintains its own log of QBXML communications in a flat file titled "qbsdklog.txt".

The location of the file may vary depending on the version of QuickBooks and the operating system you are using. Some locations include:

  • C:\Program Files\Common Files\Intuit\QuickBooks
  • C:\ProgramData\Intuit\QuickBooks
  • C:\Documents and Settings\All Users\Application Data\Intuit\QuickBooks
Any errors that occurred will be added to the bottom of the file. You may find additional information for these errors online by searching for the HR code.


If none of these solutions work for you, please feel free to contact our support department here.

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