FAXCOMEXLib – Invalid Operation Error on Windows Server 2008 (.NET) – Problem and Solution

Problem

This page discusses a scenario in which a fax service is being installed on Windows Server 2008 R2, which was previously installed on a Windows Server 2003. Sending faxes worked on the 2003 server. On the 2008 server, sending faxes using the fax as a shared printer works, but sending them programmatically fails, causing Invalid Operation errors.

The following line of code works on 2003 and fails in 2008:

JobIDs = (System.Array) faxDoc.ConnectedSubmit(faxServer);

Solution

The problem is that both the old fax (\OldServer\Fax) and the new fax (\NewServer\Fax) exist on the client machine. Remove the old fax, and the code should work.

For the full discussion regarding this issue, on the MSDN Windows Server forum, click here.