When trying to open the Overrides dialog box, you get this error;

Error: bad argument type: stringp nil

Step 1a.3 - Fitting Exchange No replacement fitting name for 22E for Sched-10 Note: This could be any fitting or pipe type described in the error. If you click ok at each error, the process will run through without these fittings

3D Details (3D Fittings) missing, only the skipoles are showing

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.

See this related HydraCARD also;  https://hydracards.hydratecinc.com/cards/card-1144

Command failure for external command ... System.IO.FileNotFoundException ... File name 'AWSSDK'

When starting the AutoCALC process, you get this error;

Could not find fitting match for Pump Only/Test Point Please check!!

You also see an Accessing Database window with a partial green progress bar.

No Operating Heads of Flows Found!!  Please check...

No error occurs but HydraCAD will not properly load and Hcad commands do not work.  

A quick test is to select the drop menu [File|New], select the template file 'HydraCAD Imperial Default.dwt'.  

The Drawing Setup window should appear but it does not, it loads straight into a blank drawing.

This is what you should see (press F2 to review the text window);

Instead you only see;

HCAD_ADS r4 functions Loaded.

AutoCAD menu utilities loaded.
Requires an integer between 0 and 32767.

3dFitting registry keys found

Requires an integer between 0 and 32767. 
 

When attempting to create a 3D model, you get the error; Please switch to System Model to Annotate Drops and Sprigs plus

System.NullReferenceException: Object reference not set to an instance of an object

at HCADexports.RevitConversion.create_hydrapipes_from_db()

at HCADexports.RevitConversion.create_hydrafittings_from_db(List'1 pipes, List'1 heads)

Auto Adjust Fittings defaults to unchecked.

layer override set up for this viewport or layer is frozen in "viewport freeze" Layers not displaying

Error 52 trying to insert fittings for calculations. Error 71 disk not ready error trying to use the sizing button. error 52 or 71

HydraCALC is calculating the equivalent lengths wrong 

A sprinkler head is drawn in space and is not connect to anything. When the drawing is raised a Hydrafitting (cap) is placed on the head. if the purge command is invoked it will cause a fatal error. Fatal error Purge V51

1. Corrupt external data 2. 3D Head Block set wrong. show fittings HydraCAD V5x

Step 1a.3 - Attaching Fittings - Fitting is a... Then Runtime Error 5 Invalid Procedure Call or Argument

Fitting Exchange No replacement fitting name for...

When attempting to 'Show Fittings' (SHF command), user gets an AutoCAD Fatal Error.

Create 3D Model causes a fatal error

blue beam loaded on machine (a pdf writer) 3dfittings unhandled exceptio

Error occurs when "Add Calculation Fittings" is used when running AutoCALC the first time after a new install. A registry entry for one of the Pipe Schedule properties is not set in the registry. (The Pipe Schedule is connected to fittings definitions.) error 75

Riser Nipple cut dimension changed to the wrong value after going into the 3D System Model. The Riser Nipple show the wrong takeout value for the sp TakeOut & ep TakeOut properties. This was caused by the SHOW FITTINGS command. HydraCAD v5x.any