When attempting to run the NWCOUT command, you get an 'unknown command' error message;

When attempting to create a Persistent Model, you get the error message;

Please click Apply and restart command.  Thank you.

Rinse and repeat each time

When trying to export to Navis, you get this error message;

TWO SYMPTOMS:

Drawing fittings and pipe look disjointed, like that time an alien team of scientists were performing out-of-phase medical experiments on the Voyager crew.

Or, on the way into Revit, you get this error;

Error (must be addressed in order to continue)

Revit has experienced an unexpected error.  The operation has been cancelled to protect your project from corruption

Deleted element

When reporting the error, you may see this;

Hashtable head_table, Hashtable FLXpipeTable, List '1 listFtgs, flexpipes PipeTypeInfo ptInfo

While importing an AutoCAD model into Revit, you get errors listed below;

After buiding your 3D risers, raising to 3D, exporting to a Persistent Model and Navisworks successfully, your 3D riser is missing, with the exception of the skipoles

Your layers are on and the 3D_DETAIL layer is present, unlocked, thawed and visible, you just can't see the pipe and fittings.  The one customer reporting this said they disappear if the drawing is closed then re-opened.  They'll be visible in viewports as well, just not in 2D view.

Missing commands on Add in for HydraCAD when trying to generate a RevitLink conversion

This error may start out as "Could not load default information for the Pipe Model settings"

But will then turn into an AutoCAD fatal error.

When selecting the Navis Toolkit then the SETUP button, you get the error;

AutoCAD Error Aborting

Fatal Error: Unhandled Access Violation 

Retrieve HydratecRevitContent is missing from the AddIns - Hydratec pulldown menu in Revit

Sprinkler heads were not properly defined with a part number within the HydraCAD drawing. Therefore, Revit used a default sprinkler head symbol which happened to be a pendent sprinkler symbol. Revit