Error: Invalid Duct Fitting K-Factor Database

Issue

You receive an error that says Invalid Duct Fitting K-Factor Database when drawing or modifying duct in Revit MEP

Solution

This issue can sometimes typically affects Vista users only.  To resolve this, Revit MEP needs to be run once as Administrator.

Here are the steps to clear this error:

1. Close Revit MEP
2. Right-click on the Revit MEP shortcut
3. Select Run as...
4. Select Administrator
5. Close Revit MEP
6. Launch Revit MEP as the current user
   

If the behavior persists, it is a result of a 3rd-party DLL not being registered properly when installing Revit MEP.  The following are steps to manually register the DLL, which should clear the above error. Please make sure to replace "<Revit MEP product year>" with the correct product year. 

1. Click on Start…Run
2. Type regsvr32 "C:\Program Files\Autodesk\<Revit MEP product year>\Program\ASHRAEDUCTDLL.dll" in the window
3. Click Ok

A dialog box indicating that the DLL was registered successfully should appear.  If not, please proceed to the steps below.

1. Click on Start…Programs..Accessories
2. Right-click on Command Prompt
3. Select Run as…
4. Select Administrator
5. In the command prompt, type CD \ to get back to the root of C:
6. Type cd Program Files\Autodesk\<Revit MEP product year>\Program
7. Type regsvr32 “ASHRAEDUCTDLL.dll"