diff --git a/Header.pas b/Header.pas
index b80a242..9c3e27d 100644
--- a/Header.pas
+++ b/Header.pas
@@ -18,7 +18,7 @@ uses CCommon, MM, Scanner, Symbol, CGI;
 {$segment 'SCANNER'}
 
 const
-   symFileVersion = 21;                 {version number of .sym file format}
+   symFileVersion = 22;                 {version number of .sym file format}
 
 var
    inhibitHeader: boolean;		{should .sym includes be blocked?}
diff --git a/Scanner.pas b/Scanner.pas
index 3bd09db..bab212a 100644
--- a/Scanner.pas
+++ b/Scanner.pas
@@ -2943,6 +2943,8 @@ var
                   bPtr^ := mPtr^.next
                else
                   lastPtr^.next := mPtr^.next;
+               if mPtr^.saved then
+                  TermHeader;
                end; {else}
             goto 1;
             end; {if}
diff --git a/cc.notes b/cc.notes
index 5260f3b..d16ad0d 100644
--- a/cc.notes
+++ b/cc.notes
@@ -1775,6 +1775,8 @@ int foo(int[42]);
 
 179. Macro definitions or header search paths specified via the cc= portion of the command line could be saved in the .sym file and applied to subsequent compilations, even if they were no longer specified on the command line.
 
+180. Certain #undef directives might be ignored when using a .sym file.
+
 -- Bugs from C 2.1.0 that have been fixed -----------------------------------
 
 1.  In some situations, fread() reread the first 1K or so of the file.