When trying to run the calculation, you get the message, 

"The system flow demand of ### exceeds the maximum rated flow as indicated in the Pump Curve for the pump with the inlet of PI and outlet of PO.  The calculation will not continue"

But your flow is a very large number

The font of your vertical pipes do not match the font of your pipe dimensions

When running the Line Couplings command (LC), you get the error, "No branch lines found crossing the line(s) you picked", even though it's 100% a fact the lines are intersecting

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.

HydraLIST - Msg #10010

An ERROR5 has occured!  Invalid procedure call or argument error 5

OR

An ERROR76 has occured...  Path not found

The error occured in; Module - RegModule SubRoutine - Set VB Dev

When printing final, you get this error message

"Error during Cover Sheet print, possibly due to missing .DAT file"

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:

When I use Pretty Sprinklers, all the nodes that were attached to my sprinklers when using All Ref Points disappeared. 
When trying to get them back by re-running All Ref Points, they don't reappear.

When I use Pretty Sprinklers, all the nodes that were attached to my sprinklers when using All Ref Points disappeared. 
When trying to get them back by re-running All Ref Points, they don't reappear.

Run-time Error 339

"Component tab32x30.OCX, spr32x25.OCX, spr32x35.OCX (or a different .OCX file) or one of its dependencies not correctly registered"  "A file is missing or invalid"