--- a/config/rules.mk
+++ b/config/rules.mk
@@ -148,17 +148,32 @@ EMBED_MANIFEST_AT=2
 
 endif # MKSHLIB
 endif # FORCE_SHARED_LIB
 endif # LIBRARY
 
 ifeq ($(OS_ARCH),WINNT)
 ifndef GNU_CC
 
+#
+# Unless we're building SIMPLE_PROGRAMS, all C++ files share a PDB file per
+# directory. For parallel builds, this PDB file is shared and locked by
+# MSPDBSRV.EXE, starting with MSVC8 SP1. If you're using MSVC 7.1 or MSVC8
+# without SP1, don't do parallel builds.
+#
+# The final PDB for libraries and programs is created by the linker and uses
+# a different name from the single PDB file created by the compiler. See
+# bug 462740.
+#
+
+ifdef SIMPLE_PROGRAMS
 COMPILE_PDB_FLAG ?= -Fd$(basename $(@F)).pdb
+else
+COMPILE_PDB_FLAG ?= -Fdgenerated.pdb
+endif
 COMPILE_CFLAGS += $(COMPILE_PDB_FLAG)
 COMPILE_CXXFLAGS += $(COMPILE_PDB_FLAG)
 
 LINK_PDBFILE ?= $(basename $(@F)).pdb
 ifdef MOZ_DEBUG
 CODFILE=$(basename $(@F)).cod
 endif