diff --git a/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs b/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs
index ff02a8dbb2..02fb43d913 100644
--- a/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs
+++ b/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs
@@ -170,11 +170,10 @@ namespace Microsoft.PowerShell
     internal class CommandLineParameterParser
     {
         internal static string[] validParameters = {
-            "psconsoleFile",
             "version",
             "nologo",
             "noexit",
-#if !CORECLR
+#if STAMODE
             "sta",
             "mta",
 #endif
@@ -251,14 +250,6 @@ namespace Microsoft.PowerShell
             }
         }
 
-        internal bool ImportSystemModules
-        {
-            get
-            {
-                return _importSystemModules;
-            }
-        }
-
         internal bool SkipProfiles
         {
             get
@@ -416,6 +407,7 @@ namespace Microsoft.PowerShell
             }
         }
 
+#if STAMODE
         internal bool StaMode
         {
             get
@@ -426,17 +418,14 @@ namespace Microsoft.PowerShell
                 }
                 else
                 {
-#if CORECLR
                     // Nano doesn't support STA COM apartment, so on Nano powershell has to use MTA as the default.
-                    return false;
-#else
+                    // return false;
                     // Win8: 182409 PowerShell 3.0 should run in STA mode by default
                     return true;
-#endif
                 }
             }
         }
-
+#endif
 
         /// <summary>
         ///
@@ -554,10 +543,6 @@ namespace Microsoft.PowerShell
                     _noExit = true;
                     noexitSeen = true;
                 }
-                else if (MatchSwitch(switchKey, "importsystemmodules", "imp"))
-                {
-                    _importSystemModules = true;
-                }
                 else if (MatchSwitch(switchKey, "noprofile", "nop"))
                 {
                     _skipUserInit = true;
@@ -728,7 +713,8 @@ namespace Microsoft.PowerShell
                         break;
                     }
                 }
-#if !CORECLR  // explicit setting of the ApartmentState Not supported on NanoServer
+#if STAMODE
+                // explicit setting of the ApartmentState Not supported on NanoServer
                 else if (MatchSwitch(switchKey, "sta", "s"))
                 {
                     if (_staMode.HasValue)
@@ -1184,6 +1170,7 @@ namespace Microsoft.PowerShell
         private string _helpText;
         private bool _abortStartup;
         private bool _skipUserInit;
+#if STAMODE
         // Win8: 182409 PowerShell 3.0 should run in STA mode by default
         // -sta and -mta are mutually exclusive..so tracking them using nullable boolean
         // if true, then sta is specified on the command line.
@@ -1191,6 +1178,7 @@ namespace Microsoft.PowerShell
         // if null, then none is specified on the command line..use default in this case
         // default is sta.
         private bool? _staMode = null;
+#endif
         private bool _noExit = true;
         private bool _explicitReadCommandsFromStdin;
         private bool _noPrompt;
@@ -1203,7 +1191,6 @@ namespace Microsoft.PowerShell
         private Collection<CommandParameter> _collectedArgs = new Collection<CommandParameter>();
         private string _file;
         private string _executionPolicy;
-        private bool _importSystemModules = false;
     }
 }   // namespace
 
diff --git a/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs b/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs
index cb1bd8992b..a58906c913 100644
--- a/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs
+++ b/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs
@@ -1435,7 +1435,11 @@ namespace Microsoft.PowerShell
 
                 // NTRAID#Windows Out Of Band Releases-915506-2005/09/09
                 // Removed HandleUnexpectedExceptions infrastructure
-                exitCode = DoRunspaceLoop(cpp.InitialCommand, cpp.SkipProfiles, cpp.Args, cpp.StaMode, cpp.ImportSystemModules, cpp.ConfigurationName);
+#if STAMODE
+                exitCode = DoRunspaceLoop(cpp.InitialCommand, cpp.SkipProfiles, cpp.Args, cpp.StaMode, cpp.ConfigurationName);
+#else
+                exitCode = DoRunspaceLoop(cpp.InitialCommand, cpp.SkipProfiles, cpp.Args, false, cpp.ConfigurationName);
+#endif
             }
             while (false);
 
@@ -1469,14 +1473,13 @@ namespace Microsoft.PowerShell
         /// The process exit code to be returned by Main.
         ///
         /// </returns>
-        private uint DoRunspaceLoop(string initialCommand, bool skipProfiles, Collection<CommandParameter> initialCommandArgs, bool staMode,
-            bool importSystemModules, string configurationName)
+        private uint DoRunspaceLoop(string initialCommand, bool skipProfiles, Collection<CommandParameter> initialCommandArgs, bool staMode, string configurationName)
         {
             ExitCode = ExitCodeSuccess;
 
             while (!ShouldEndSession)
             {
-                RunspaceCreationEventArgs args = new RunspaceCreationEventArgs(initialCommand, skipProfiles, staMode, importSystemModules, configurationName, initialCommandArgs);
+                RunspaceCreationEventArgs args = new RunspaceCreationEventArgs(initialCommand, skipProfiles, staMode, configurationName, initialCommandArgs);
                 CreateRunspace(args);
 
                 if (ExitCode == ExitCodeInitFailure) { break; }
@@ -1515,10 +1518,12 @@ namespace Microsoft.PowerShell
 
                 _runspaceRef.Runspace.Close();
                 _runspaceRef = null;
+#if STAMODE
                 if (staMode) // don't recycle the Runspace in STA mode
                 {
                     ShouldEndSession = true;
                 }
+#endif
             }
 
             return ExitCode;
@@ -1556,7 +1561,11 @@ namespace Microsoft.PowerShell
             {
                 args = runspaceCreationArgs as RunspaceCreationEventArgs;
                 Dbg.Assert(args != null, "Event Arguments to CreateRunspace should not be null");
-                DoCreateRunspace(args.InitialCommand, args.SkipProfiles, args.StaMode, args.ImportSystemModules, args.ConfigurationName, args.InitialCommandArgs);
+#if STAMODE
+                DoCreateRunspace(args.InitialCommand, args.SkipProfiles, args.StaMode, args.ConfigurationName, args.InitialCommandArgs);
+#else
+                DoCreateRunspace(args.InitialCommand, args.SkipProfiles, false, args.ConfigurationName, args.InitialCommandArgs);
+#endif
             }
             catch (ConsoleHostStartupException startupException)
             {
@@ -1571,7 +1580,7 @@ namespace Microsoft.PowerShell
         [SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
         private void InitializeRunspace(string initialCommand, bool skipProfiles, Collection<CommandParameter> initialCommandArgs)
         {
-            DoCreateRunspace(initialCommand, skipProfiles, staMode: false, importSystemModules: false, configurationName: null, initialCommandArgs: initialCommandArgs);
+            DoCreateRunspace(initialCommand, skipProfiles, staMode: false, configurationName: null, initialCommandArgs: initialCommandArgs);
         }
 
         private bool LoadPSReadline()
@@ -1594,8 +1603,7 @@ namespace Microsoft.PowerShell
         ///
         /// </summary>
 
-        //private void CreateRunspace(string initialCommand, bool skipProfiles, bool staMode, Collection<CommandParameter> initialCommandArgs)
-        private void DoCreateRunspace(string initialCommand, bool skipProfiles, bool staMode, bool importSystemModules, string configurationName, Collection<CommandParameter> initialCommandArgs)
+        private void DoCreateRunspace(string initialCommand, bool skipProfiles, bool staMode, string configurationName, Collection<CommandParameter> initialCommandArgs)
         {
             Dbg.Assert(_runspaceRef == null, "runspace should be null");
 #if !DEBUG
@@ -1682,11 +1690,12 @@ namespace Microsoft.PowerShell
             // Record how long it took from process start to runspace open for telemetry.
             _readyForInputTimeInMS = (DateTime.Now - Process.GetCurrentProcess().StartTime).TotalMilliseconds;
 
-            DoRunspaceInitialization(importSystemModules, skipProfiles, initialCommand, configurationName, initialCommandArgs);
+            DoRunspaceInitialization(skipProfiles, initialCommand, configurationName, initialCommandArgs);
         }
 
         private void OpenConsoleRunspace(Runspace runspace, bool staMode)
         {
+#if STAMODE
             // staMode will have following values:
             // On FullPS: 'true'/'false' = default('true'=STA) + possibility of overload through cmdline parameter '-mta'
             // On NanoPS: always 'false' = default('false'=MTA) + NO possibility of overload through cmdline parameter '-mta'
@@ -1694,12 +1703,10 @@ namespace Microsoft.PowerShell
             if (staMode)
             {
                 // we can't change ApartmentStates on CoreCLR
-#if !CORECLR
                 runspace.ApartmentState = ApartmentState.STA;
-#endif
-                runspace.ThreadOptions = PSThreadOptions.ReuseThread;
             }
-
+#endif
+            runspace.ThreadOptions = PSThreadOptions.ReuseThread;
             runspace.EngineActivityId = EtwActivity.GetActivityId();
 
             s_runspaceInitTracer.WriteLine("Calling Runspace.Open");
@@ -1707,7 +1714,7 @@ namespace Microsoft.PowerShell
             runspace.Open();
         }
 
-        private void DoRunspaceInitialization(bool importSystemModules, bool skipProfiles, string initialCommand, string configurationName, Collection<CommandParameter> initialCommandArgs)
+        private void DoRunspaceInitialization(bool skipProfiles, string initialCommand, string configurationName, Collection<CommandParameter> initialCommandArgs)
         {
             if (_runspaceRef.Runspace.Debugger != null)
             {
@@ -1717,12 +1724,6 @@ namespace Microsoft.PowerShell
 
             Executor exec = new Executor(this, false, false);
 
-            // Run import system modules command
-            if (importSystemModules)
-            {
-                Exception exception = InitializeRunspaceHelper("ImportSystemModules", exec, Executor.ExecutionOptions.None);
-            }
-
             if (!string.IsNullOrEmpty(configurationName))
             {
                 // If an endpoint configuration is specified then create a loop-back remote runspace targeting
@@ -3015,28 +3016,28 @@ namespace Microsoft.PowerShell
         /// <param name="initialCommand"> </param>
         /// <param name="skipProfiles"></param>
         /// <param name="staMode"></param>
-        /// <param name="importSystemModules"></param>
         /// <param name="configurationName"></param>
         /// <param name="initialCommandArgs"></param>
         internal RunspaceCreationEventArgs(string initialCommand,
                                            bool skipProfiles,
                                            bool staMode,
-                                           bool importSystemModules,
                                            string configurationName,
                                            Collection<CommandParameter> initialCommandArgs)
         {
             InitialCommand = initialCommand;
             SkipProfiles = skipProfiles;
+#if STAMODE
             StaMode = staMode;
-            ImportSystemModules = importSystemModules;
+#endif
             ConfigurationName = configurationName;
             InitialCommandArgs = initialCommandArgs;
         }
 
         internal string InitialCommand { get; set; }
         internal bool SkipProfiles { get; set; }
+#if STAMODE
         internal bool StaMode { get; set; }
-        internal bool ImportSystemModules { get; set; }
+#endif
         internal string ConfigurationName { get; set; }
         internal Collection<CommandParameter> InitialCommandArgs { get; set; }
     }
diff --git a/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleShell.cs b/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleShell.cs
index 227ee91aba..c5e0d332c0 100644
--- a/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleShell.cs
+++ b/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleShell.cs
@@ -25,18 +25,6 @@ namespace Microsoft.PowerShell
         {
             return Start(null, bannerText, helpText, null, args);
         }
-#else
-        /// <summary>Entry point in to ConsoleShell. This method is called by main of minishell.</summary>
-        /// <param name="configuration">Configuration information which is used to create Runspace.</param>
-        /// <param name="bannerText">Banner text to be displayed by ConsoleHost</param>
-        /// <param name="helpText">Help text for minishell. This is displayed on 'minishell -?'.</param>
-        /// <param name="args">Commandline parameters specified by user.</param>
-        /// <returns>An integer value which should be used as exit code for the process.</returns>
-        public static int Start(RunspaceConfiguration configuration, string bannerText, string helpText, string[] args)
-        {
-            return Start(configuration, bannerText, helpText, null, args);
-        }
-#endif
 
         /// <summary>
         ///
diff --git a/src/System.Management.Automation/engine/InitialSessionState.cs b/src/System.Management.Automation/engine/InitialSessionState.cs
index e47498fdf5..e20aa7a30c 100644
--- a/src/System.Management.Automation/engine/InitialSessionState.cs
+++ b/src/System.Management.Automation/engine/InitialSessionState.cs
@@ -4162,14 +4162,6 @@ End
 }
         ";
 
-        /// <summary>
-        /// This is the default function to use for 'Import System Modules'.
-        /// </summary>
-        /// <remarks>
-        /// Win8: 320909. Retaining the original definition to ensure backward compatability.
-        /// </remarks>
-        private static string s_importSystemModulesText = @"";
-
         /// <summary>
         /// This is the default function to use for clear-host. On Windows it rewrites the
         /// host, and on Linux, it delegates to the native binary, 'clear'.
@@ -4971,8 +4963,6 @@ if($paths) {
 
             SessionStateFunctionEntry.GetDelayParsedFunctionEntry("cd..", "Set-Location ..", isProductCode: true),
             SessionStateFunctionEntry.GetDelayParsedFunctionEntry("cd\\", "Set-Location \\", isProductCode: true),
-            // Win8: 320909. Retaining the original definition to ensure backward compatability.
-            SessionStateFunctionEntry.GetDelayParsedFunctionEntry("ImportSystemModules", s_importSystemModulesText, isProductCode: true),
             SessionStateFunctionEntry.GetDelayParsedFunctionEntry("Pause",
                 string.Concat("$null = Read-Host '", CodeGeneration.EscapeSingleQuotedStringContent(RunspaceInit.PauseDefinitionString),"'"), isProductCode: true)
         };