This command clears the active workspace and gives the report "clear ws".  The active workspace is lost.  The name of a clear workspace is CLEAR WS.  System variables are initialised with their default values as described in System Variables.

In GUI implementations of Dyalog APL, )CLEAR expunges all GUI objects, discards any unprocessed events in the event queue and resets the properties of the Root object  '.'  to their default values.

Apart from .NET objects, the contents of the session namespace ⎕SE are not affected. .NET objects in ⎕SE are disconnected from .NET because )CLEAR closes the current .NET AppDomain.