diff --git a/BaseTools/Source/Python/Workspace/MetaFileParser.py b/BaseTools/Source/Python/Workspace/MetaFileParser.py
index 512b172352..1880148a6d 100644
--- a/BaseTools/Source/Python/Workspace/MetaFileParser.py
+++ b/BaseTools/Source/Python/Workspace/MetaFileParser.py
@@ -1400,6 +1400,17 @@ class DscParser(MetaFileParser):
 
             self._Scope = [[S1, S2, S3]]
             #
+            # Expand macros in arch field for all records so that per-module
+            # sub-items (e.g. <LibraryClasses> under [Components.$(PEI_ARCH)])
+            # resolve correctly, not just the Component record itself.
+            #
+            self._Scope[0][0] = ReplaceMacro(self._Scope[0][0], self._Macros)
+            if '$(' in self._Scope[0][0] and S1 != TAB_ARCH_COMMON:
+                EdkLogger.warn("Parser",
+                               "Macro in arch field was not resolved. "
+                               "'%s' used in section header is not defined." % S1,
+                               File=self._FileWithError, Line=LineStart)
+            #
             # For !include directive, handle it specially,
             # merge arch and module type in case of duplicate items
             #
@@ -1712,7 +1723,6 @@ class DscParser(MetaFileParser):
 
     def __ProcessComponent(self):
         self._ValueList[0] = ReplaceMacro(self._ValueList[0], self._Macros)
-        self._Scope[0][0] = ReplaceMacro(self._Scope[0][0], self._Macros)
 
     def __ProcessBuildOption(self):
         self._ValueList = [ReplaceMacro(Value, self._Macros, RaiseError=False)