When opening HydraCAD and trying to open a drawing or a template, you get the error message; 

Also happened when layers were isolated trying to burst objects

'unrecognized version and cannot be read'

When opening HydraCAD, you get this error

Unhandled Exception...DAO32Server...

Layer Notification Warning

Unreconciled new layers exist in the drawing

Unhandled exception.  eAtMaxReaders

When opening HydraCAD, you get the error message saying, "The Ribbon does not have any tabs or panels currently loaded"

When opening AutoCAD, usually after a fresh install, you're greeted with this error message'

InstallPath registry key not found.  HydraCAD must be re-installed using the current profile.  Defaulting to C:

Soon after installing HydraCAD, upon opening it you get an Unhandled Exception error.

The component 'Autodesk.AutoCAD.StatusBar.ContextMenuHost' does not have a resource identified by the URI '/AcWindows;component/features/statusbar/contextmenuhose.xaml'

Error -5001 in HydraCAD.  When opening Hydracad, it gives the following error:

Hydracad, doesn’t function properly thereafter.

When trying to get into HydraCAD, you get this error message.

Your HCAD_ENV.INI file is corrupted.
This is found in the \HES\HYDRACADWER50\PROGRAMS\VersionXx
folder where XX is the version you are using. Please copy this file from
a working machine and reopen HydraCAD or contact Hydratec for
assistance
 

Opening a drawing is taking a long time.  The process is very slow.

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