Interop.QBPOSXMLRPLIB, Version= Error Message

If you try to add the qwc file to Intuit’s webconnector and you receive the following message, here’s what you need to do to resolve it

Error Message:

QBWebConnector.SOAPWebService.ConnectToQB() : Error connecting to QuickBooks. Error message received from QuickBooks was <Could not load file or assembly ‘Interop.QBPOSXMLRPLIB, Version=, Culture=neutral, PublicKeyToken=31d8aec643e18259′ or one of its dependencies. The system cannot find the file specified.>.


You’ll receive that message if the PC running QuickBooks Point of Sale is missing a “library” (code for windows file) used to facilitate communication between Intuit’s webconnector and Intuit’s QuickBooks Point of Sale apps. This library might not be included during the options selected during the QBPOS install. The only / easiest way to include the missing windows files from Intuit is to download and install the QuickBooks Point of Sale SDK 3.0  from Intuit. You can find the download on this page:

Be sure you download this file toward the bottom of the page:

QuickBooks Point of Sale SDK 3.0 Installer(self-extracting installer, 55MB)

You need to install that on the same PC that’s running Intuit’s webconnector and QuickBooks Point of Sale. Once installed, restart the PC and try adding the qwc file to Intuit’s webconnector.