After attempting to download the Latest Toolbox, a warning appears saying the file cannot be opened. 
Tells user to delete toolbox .rvt file and try again, but that does not work. 

When clicking the Calculate button or the OK button from the Pre-Calc Questions window, you get a Runtime-error 5,

Run-time error '5': Invalid procedure call or argument

Double-clicking your HydraCALC icon makes nothing happen.  You do not see HydraCALC open onscreen nor on your taskbar.  HydraCALC does not open other than in the task manager.

If you open your task manager and see the app "Hyd_prog.exe" open but not on your taskbar, then the application is stuck in purgatory.

Another possibility may be that it's on the taskbar but not on your screen.  That means it's open but offscreen. 

See this HydraCARD to fix that issue;  HydraCARD 565 only AFTER you've checked on the solution below.

When attempting to insert a cap, it draws the pipe and dimensions it, but it doesn't insert a cap.

However if you draw a test pipe elsewhere, it successfully inserts the cap for you

When trying to print final, the dialog box HydraVIEW, Run-time error 9, Subscript out of range

When running the "FSC Setup" to "Create FSC Definition". 
Upon finishing the block definition, the block definition is missing a crucial property for "Hydraulic equivalent length is referenced by:". This field will show blank or the default generic text and did not include the HydraCALC pipe/fitting reference information.

There is a missing HydraCALC "ImportExport" directory.

Default line text:
`Hydraulic equivalent length is referenced by: shortname with length number - longname Listing: FM`

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

When performing AutoCalc, the following error is displayed.

Unhandled Exception... startIndex cannot be larger than the length of string.
(Parameter 'startIndex').

When selecting a pipe for the Move Main command, you get a fatal error

The diameter tag HANDLE is 0000 this number is used to determin if the pipe is sloped - yielding an incorrect pipe length. Move Line / Move Main make the diameter tag HANDLE be 0000