diff --git a/BaseTools/Source/Python/Common/MultipleWorkspace.py b/BaseTools/Source/Python/Common/MultipleWorkspace.py
index ad5d48588b48..0ddb14f4b583 100644
--- a/BaseTools/Source/Python/Common/MultipleWorkspace.py
+++ b/BaseTools/Source/Python/Common/MultipleWorkspace.py
@@ -34,7 +34,7 @@ class MultipleWorkspace(object):
     #
     @classmethod
     def convertPackagePath(cls, Ws, Path):
-        if str(os.path.normcase (Path)).startswith(Ws):
+        if str(os.path.normcase (os.path.normpath(Path))).startswith(os.path.normcase(os.path.normpath(Ws))):
             return os.path.join(Ws, os.path.relpath(Path, Ws))
         return Path
 
diff --git a/BaseTools/Source/Python/Common/TargetTxtClassObject.py b/BaseTools/Source/Python/Common/TargetTxtClassObject.py
index 363c38302b8e..e741d0399caf 100644
--- a/BaseTools/Source/Python/Common/TargetTxtClassObject.py
+++ b/BaseTools/Source/Python/Common/TargetTxtClassObject.py
@@ -176,7 +176,7 @@ def _GetTarget(self):
                 ConfDirectoryPath = mws.join(os.environ["WORKSPACE"], ConfDirectoryPath)
         else:
             if "CONF_PATH" in os.environ:
-                ConfDirectoryPath = os.path.normcase(os.path.normpath(os.environ["CONF_PATH"]))
+                ConfDirectoryPath = os.path.normpath(os.environ["CONF_PATH"])
             else:
                 # Get standard WORKSPACE/Conf use the absolute path to the WORKSPACE/Conf
                 ConfDirectoryPath = mws.join(os.environ["WORKSPACE"], 'Conf')
diff --git a/BaseTools/Source/Python/Ecc/EccMain.py b/BaseTools/Source/Python/Ecc/EccMain.py
index a349cd80147f..5211d09e8dd8 100644
--- a/BaseTools/Source/Python/Ecc/EccMain.py
+++ b/BaseTools/Source/Python/Ecc/EccMain.py
@@ -63,7 +63,7 @@ def __init__(self):
         self.ParseOption()
         EdkLogger.info(time.strftime("%H:%M:%S, %b.%d %Y ", time.localtime()) + "[00:00]" + "\n")
 
-        WorkspaceDir = os.path.normcase(os.path.normpath(os.environ["WORKSPACE"]))
+        WorkspaceDir = os.path.normpath(os.environ["WORKSPACE"])
         os.environ["WORKSPACE"] = WorkspaceDir
 
         # set multiple workspace
diff --git a/BaseTools/Source/Python/GenFds/GenFds.py b/BaseTools/Source/Python/GenFds/GenFds.py
index b48fe761e051..885e01e9cc9b 100644
--- a/BaseTools/Source/Python/GenFds/GenFds.py
+++ b/BaseTools/Source/Python/GenFds/GenFds.py
@@ -134,7 +134,7 @@ def GenFdsApi(FdsCommandDict, WorkSpaceDataBase=None):
             EdkLogger.error("GenFds", PARAMETER_INVALID, "WORKSPACE is invalid",
                             ExtraData="Please use '-w' switch to pass it or set the WORKSPACE environment variable.")
         else:
-            Workspace = os.path.normcase(FdsCommandDict.get("Workspace",os.environ.get('WORKSPACE')))
+            Workspace = os.path.normpath(FdsCommandDict.get("Workspace",os.environ.get('WORKSPACE')))
             GenFdsGlobalVariable.WorkSpaceDir = Workspace
             if FdsCommandDict.get("debug"):
                 GenFdsGlobalVariable.VerboseLogger("Using Workspace:" + Workspace)
@@ -200,7 +200,7 @@ def GenFdsApi(FdsCommandDict, WorkSpaceDataBase=None):
                 ConfDirectoryPath = os.path.join(GenFdsGlobalVariable.WorkSpaceDir, ConfDirectoryPath)
         else:
             if "CONF_PATH" in os.environ:
-                ConfDirectoryPath = os.path.normcase(os.environ["CONF_PATH"])
+                ConfDirectoryPath = os.path.normpath(os.environ["CONF_PATH"])
             else:
                 # Get standard WORKSPACE/Conf, use the absolute path to the WORKSPACE/Conf
                 ConfDirectoryPath = mws.join(GenFdsGlobalVariable.WorkSpaceDir, 'Conf')
diff --git a/BaseTools/Source/Python/build/build.py b/BaseTools/Source/Python/build/build.py
index 5a4f51c58035..74b4242a1695 100755
--- a/BaseTools/Source/Python/build/build.py
+++ b/BaseTools/Source/Python/build/build.py
@@ -105,7 +105,7 @@ def CheckEnvVariable():
         EdkLogger.error("build", ATTRIBUTE_NOT_AVAILABLE, "Environment variable not found",
                         ExtraData="WORKSPACE")
 
-    WorkspaceDir = os.path.normcase(os.path.normpath(os.environ["WORKSPACE"]))
+    WorkspaceDir = os.path.normpath(os.environ["WORKSPACE"])
     if not os.path.exists(WorkspaceDir):
         EdkLogger.error("build", FILE_NOT_FOUND, "WORKSPACE doesn't exist", ExtraData=WorkspaceDir)
     elif ' ' in WorkspaceDir:
@@ -124,7 +124,7 @@ def CheckEnvVariable():
                 EdkLogger.error("build", FORMAT_NOT_SUPPORTED, "No space is allowed in PACKAGES_PATH", ExtraData=Path)
 
 
-    os.environ["EDK_TOOLS_PATH"] = os.path.normcase(os.environ["EDK_TOOLS_PATH"])
+    os.environ["EDK_TOOLS_PATH"] = os.path.normpath(os.environ["EDK_TOOLS_PATH"])
 
     # check EDK_TOOLS_PATH
     if "EDK_TOOLS_PATH" not in os.environ:
@@ -817,11 +817,11 @@ def __init__(self, Target, WorkspaceDir, BuildOptions,log_q):
         EdkLogger.quiet("%-16s = %s" % ("WORKSPACE", os.environ["WORKSPACE"]))
         if "PACKAGES_PATH" in os.environ:
             # WORKSPACE env has been converted before. Print the same path style with WORKSPACE env.
-            EdkLogger.quiet("%-16s = %s" % ("PACKAGES_PATH", os.path.normcase(os.path.normpath(os.environ["PACKAGES_PATH"]))))
+            EdkLogger.quiet("%-16s = %s" % ("PACKAGES_PATH", os.path.normpath(os.environ["PACKAGES_PATH"])))
         EdkLogger.quiet("%-16s = %s" % ("EDK_TOOLS_PATH", os.environ["EDK_TOOLS_PATH"]))
         if "EDK_TOOLS_BIN" in os.environ:
             # Print the same path style with WORKSPACE env.
-            EdkLogger.quiet("%-16s = %s" % ("EDK_TOOLS_BIN", os.path.normcase(os.path.normpath(os.environ["EDK_TOOLS_BIN"]))))
+            EdkLogger.quiet("%-16s = %s" % ("EDK_TOOLS_BIN", os.path.normpath(os.environ["EDK_TOOLS_BIN"])))
         EdkLogger.quiet("%-16s = %s" % ("CONF_PATH", GlobalData.gConfDirectory))
         if "PYTHON3_ENABLE" in os.environ:
             PYTHON3_ENABLE = os.environ["PYTHON3_ENABLE"]
@@ -2685,7 +2685,7 @@ def Main():
 
         if Option.ModuleFile:
             if os.path.isabs (Option.ModuleFile):
-                if os.path.normcase (os.path.normpath(Option.ModuleFile)).find (Workspace) == 0:
+                if os.path.normcase (os.path.normpath(Option.ModuleFile)).find (os.path.normcase(Workspace)) == 0:
                     Option.ModuleFile = NormFile(os.path.normpath(Option.ModuleFile), Workspace)
             Option.ModuleFile = PathClass(Option.ModuleFile, Workspace)
             ErrorCode, ErrorInfo = Option.ModuleFile.Validate(".inf", False)
@@ -2694,13 +2694,13 @@ def Main():
 
         if Option.PlatformFile is not None:
             if os.path.isabs (Option.PlatformFile):
-                if os.path.normcase (os.path.normpath(Option.PlatformFile)).find (Workspace) == 0:
+                if os.path.normcase (os.path.normpath(Option.PlatformFile)).find (os.path.normcase(Workspace)) == 0:
                     Option.PlatformFile = NormFile(os.path.normpath(Option.PlatformFile), Workspace)
             Option.PlatformFile = PathClass(Option.PlatformFile, Workspace)
 
         if Option.FdfFile is not None:
             if os.path.isabs (Option.FdfFile):
-                if os.path.normcase (os.path.normpath(Option.FdfFile)).find (Workspace) == 0:
+                if os.path.normcase (os.path.normpath(Option.FdfFile)).find (os.path.normcase(Workspace)) == 0:
                     Option.FdfFile = NormFile(os.path.normpath(Option.FdfFile), Workspace)
             Option.FdfFile = PathClass(Option.FdfFile, Workspace)
             ErrorCode, ErrorInfo = Option.FdfFile.Validate(".fdf", False)