Continue button is Grayed out, and I cannot proceed with my calculation.

No Ribbons / only the HydraCAD Ribbon appears, and no commands work.
Revit could not complete the external command. Could not load file or assembly. The system cannot find the specified file. 

When trying to open a calc job using [File|Open], you get a Run-time error '62': Input past end of file

When selecting Adjustable Ring Hangers for pipe sizes larger than 8" the detail does not show.

While in your viewport, your riser is visible while in the 2D Wireframe view.  However if you change the Visual Style to Conceptual or Shades of Grey/Shades of Gray, your 3D riser disappears.  You may notice if re-appears if you zoom out.

After printing your data in HydraLIST, when HydraVIEW opens you attempt to change the default printer. 

You get an error "Page Setup - Unknown filetype found 'HLTF'"

When opening HydraCALC SIZER, you get the error;  Run-time error '53': File not found

After starting the AutoLIST process, you get an error saying, "Error with Drop/Sprig annotation...  This one will be displayed"

After clicking OK, HydraLIST opens but you won't see any cut lengths of your sprigs and drops in the layer DropSprigTextCL

During the install of HydraCAD, you get an error, "Setup Needs the Next Disk, Please insert disk 1 that contains the file data2cab"

Revit could not complete the external command... Revit encountered a Attempt to modify the model outside of transaction

When closing a drawing in 3D, and later re-opening and returning to 2D, some of the drawing symbols show up looking like outlines (Hangers, Sprinklers, etc)

HydraCAD Critical Error... Visual Lisp not available

Error appears when opening Hangers

Failed to load the following families: z_Pipe Elevation Marker

Revit could not complete the external command... Missing file

Runtime Error 5 running FDT command on Metric drawing

Blacked out cells in Head Selector dialog

After clicking the Start AutoCALCs (SAL command) button but BEFORE the AutoCALC Setup window, you get the error; 

Unhandled exception has occurred in a component in your application. If you click Continue, the application will ignore this error and attempt to continue.

The input string '1◆' was not in a correct format.

 No inch marks (“) after the pipe diameter or there are but you prefer to remove them

After opening AutoCAD and a drawing, you have a dead area where you can't draw nor does anything display.  Usually next to a compressed palette.  Note in the image below how the crosshairs do not extend to this area.

Yellow part numbers that do not list