When trying to raise to 3D, the following error message pops up;

Autodesk.AutoCAD.Runtime.Exception: eKeyNotFound

and

Exception Occured at AddURLToHyperlinks::HydraHeads

The drawing will continue to raise up to 3D, but there will be no 3D sprinkler heads shown

When attempting to define a sprinkler head, after selecting NEW SYMBOL and choosing a sprinkler head, when your click OK to set its definitions, nothing happens and you go back to a command prompt.  The defininition window does not appear at all.  If you notice grey colored text,this is also a cue there is something wrong

When trying to raise to 3D, show model, show system model, you get the error;

Access denied to HydraPipe Utilities

and

System.NullReferenceException: Object reference not set to an instance of an object at HCADexports.RevitConversion.create_hydrapipes_from_db()

Upon calculating a file, the error message, "Failed to launch C:\HES\Hydratec for revit\programs\calcdiagnose.exe" pops up.

Was preceeded by these messages;

Plus this;  Number of Loops -1 and or Nodes with undesignated elevations

No Pipe Types are displayed in the Pipes ...  Pipe Types...  drop down list

                       -or-

Pipe Types known to be selected are not included in the  Pipe...  Pipe Types...  drop down list

When trying to create a new Info Sheet, you're greeted with the error; 

Error during load of .INF data, mismatched file versus form

Unable to Load HCADWIN.MNL

ARX does not load. HydraCAD functions do not work

AutoCAD Options Files tab contains greyed out entries. No entries in the Files tab can be edited, added or deleted

When viewing the final calc printout, the info sheet shows the line,

text1(35) - invisible

This error appears immediately when trying to run Create Stocklist, the dialog box never appears. 

Revit could not complete the external command... System.NullReferenceException

Install or Update appears to hang.

When opening Valve Selector received the following message: Initialization Failed
Application failed to initialize.

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 

None

Command Line in AutoCAD is missing

While trying to calculate a job, an error message pops up saying the following

"Error in Calc Engine"

Error in processing data of calculation;

-If this is a grid, uncheck 'Autopeak' and try again or,

-Confirm the node you set as the calculation source node exists in your input or,

- Check for incorrect values in your densities, areas or pressures

Unhandled Exception has occurred in a component in your application.

One of the identified items was in an invalid format

During running your calculation, and after receiving the summary regarding your safety margin, you get a similar error.

You'll then likely get these errors, up to 3 times.

Be aware these windows may be BEHIND the calc window, so move the calc window out of the way if it looks like it has crashed or is hung; 

When trying to insert a riser nipple/vertical pipe, you get a FATAL ERROR:  Unhandled Access Violation. 592A00h or 8B2A00h

List of available hangers is blank or very short...

Missing Basic Adjustable Ring Hanger

Missing Hanger Families

Trying run a calculation as stand-alone, or via AutoCAD/AutoCALC or Revit/AutoCALC, you get this error message;

Run-time error 339:  Runtime error 339  Runtime 339
Component 'MSCOMCTL.OCX' or one of its dependencies not correctly registered: a file is missing or invalid

It's likely a job without a pump works, but one with a pump crashes