diff --git a/src/d_main.cpp b/src/d_main.cpp
index a44399ff9..0919d3acb 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -2054,6 +2054,21 @@ static void CheckCmdLine()
 	}
 }
 
+//==========================================================================
+//
+// FinalGC
+//
+// If this doesn't free everything, the debug CRT will let us know.
+//
+//==========================================================================
+
+static void FinalGC()
+{
+	Args = NULL;
+	GC::FullGC();
+	GC::DelSoftRootHead();	// the soft root head will not be collected by a GC so we have to do it explicitly
+}
+
 //==========================================================================
 //
 // D_DoomMain
@@ -2072,6 +2087,7 @@ void D_DoomMain (void)
 
 	D_DoomInit();
 	PClass::StaticInit ();
+	atterm(FinalGC);
 
 	// [RH] Make sure zdoom.pk3 is always loaded,
 	// as it contains magic stuff we need.
diff --git a/src/dobject.cpp b/src/dobject.cpp
index 9f749aeaa..191fa3c43 100644
--- a/src/dobject.cpp
+++ b/src/dobject.cpp
@@ -453,8 +453,9 @@ size_t DObject::PropagateMark()
 			GC::Mark((DObject **)((BYTE *)this + *offsets));
 			offsets++;
 		}
+		return info->Size;
 	}
-	return info->Size;
+	return 0;
 }
 
 size_t DObject::PointerSubstitution (DObject *old, DObject *notOld)
diff --git a/src/farchive.cpp b/src/farchive.cpp
index 9c128e0f7..6b0fafd18 100644
--- a/src/farchive.cpp
+++ b/src/farchive.cpp
@@ -401,10 +401,13 @@ void FCompressedFile::Explode ()
 			uLong newlen;
 
 			newlen = expandsize;
+			_heapchk();
 			r = uncompress (expand, &newlen, m_Buffer + 8, cprlen);
 			if (r != Z_OK || newlen != expandsize)
 			{
+				_heapchk();
 				M_Free (expand);
+				_heapchk();
 				I_Error ("Could not decompress cfile");
 			}
 		}
@@ -497,7 +500,18 @@ bool FCompressedMemFile::Reopen ()
 		m_Mode = EReading;
 		m_Buffer = m_ImplodedBuffer;
 		m_SourceFromMem = true;
-		Explode ();
+		try
+		{
+			Explode ();
+		}
+		catch(...)
+		{
+			// If we just leave things as they are, m_Buffer and m_ImplodedBuffer
+			// both point to the same memory block and both will try to free it.
+			m_Buffer = NULL;
+			m_SourceFromMem = false;
+			throw;
+		}
 		m_SourceFromMem = false;
 		return true;
 	}
diff --git a/src/sdl/i_main.cpp b/src/sdl/i_main.cpp
index 5c0bfa506..36cf49617 100644
--- a/src/sdl/i_main.cpp
+++ b/src/sdl/i_main.cpp
@@ -138,20 +138,6 @@ void STACK_ARGS call_terms ()
 	}
 }
 
-//==========================================================================
-//
-// FinalGC
-//
-// Collect garbage one last time before exiting.
-//
-//==========================================================================
-
-static void FinalGC()
-{
-	Args = NULL;
-	GC::FullGC();
-}
-
 static void STACK_ARGS NewFailure ()
 {
     I_FatalError ("Failed to allocate memory from system heap");
@@ -323,7 +309,6 @@ int main (int argc, char **argv)
     try
     {
 		Args = new DArgs(argc, argv);
-		atterm(FinalGC);
 
 		/*
 		  killough 1/98:
diff --git a/src/win32/i_main.cpp b/src/win32/i_main.cpp
index 2a65e8c9c..4079fcae7 100644
--- a/src/win32/i_main.cpp
+++ b/src/win32/i_main.cpp
@@ -251,21 +251,6 @@ static void UnWTS (void)
 	}
 }
 
-//==========================================================================
-//
-// FinalGC
-//
-// If this doesn't free everything, the debug CRT will let us know.
-//
-//==========================================================================
-
-static void FinalGC()
-{
-	Args = NULL;
-	GC::FullGC();
-	GC::DelSoftRootHead();	// the soft root head will not be collected by a GC so we have to do it explicitly
-}
-
 //==========================================================================
 //
 // LayoutErrorPane
@@ -828,7 +813,6 @@ void DoMain (HINSTANCE hInstance)
 #endif
 
 		Args = new DArgs(__argc, __argv);
-		atterm(FinalGC);
 
 		// Under XP, get our session ID so we can know when the user changes/locks sessions.
 		// Since we need to remain binary compatible with older versions of Windows, we