Runtime Error 5 Invalid Procedure Call or Argument 

Using the Sprinkler Spacing and Layout tool: Revit encountered a Autodesk.Revit.Exceptions.InvalidObjectException: The referenced object is not valid, possibly because it has been deleted from the database, or it's creation was undone.

Revit could not complete the external command Object Reference not Valid

Line/Main annotations do not populate with Line/Main numbers after running the calculation.

Too many Water Supplies! error message when using the Define Water Supply function

Error Message - The duct/pipe has been modified to be in the opposite direction causing the connections to be invalid. The referenced object is not valid, possibly because it has been deleted from the database, or its creation was undone.

Error placing Reference Points or Demand Area annotation.: System NullReferenceException: Object reference not set to an instance of an object. nodes reference finish

When making a 3D view, nothing shows up.

There are no ribbons visible after installing the software. The HydraCAD ribbon is missing.

When using connect heads to pipes AND the family Fire Protection Lines Threaded AND connecting three (3) or more sprinklers, one (1) pipe segment disappears during the command.

Unhandled Exception... Details... System.NullReferenceException: Object reference not set to an instance of an object. at HCAD_HUI.frmPipeTypeSchedule.cmdContinue_Click

Inserting sprinklers using the spacing an layout tool Import Errors message box - message Autodesk.Revit.InvalidOperationsException: failed to insert transition

Revit could not complete the external command.... Details: Name must be unique... At HCAD_Revit_Tools.CAD3.Insert_Pump.Go

Setup a hanger, insert a hanger, see a hanger insert, then the Run Setup dialog box comes up, pick OK and *Poof*, no hanger.

Error placing reference points or demand area annotation...... System.IndexOutOfRangeException: Index was outside the bounds of the array "Make Pipe Type Info Array String"

1. Hardware lock drivers not properly installed.
2. May 15, 2018 : v56 + Win10, unknown n/a Dialog box v56 only

At end of AutoCalc steps, Path not Found, HydraCALC does not open

Revit cannot complete the external command unhandled exception Object not set to an instance of an Object

Using the Sprinkler Spacing and Layout tool: System.IndexOutOfRangeException: Index was outside the bounds of the array.

Step 2.3 - Can also show up as This Calculation has gone 200 passes...