diff --git a/cde/programs/dtappbuilder/src/ab/Makefile.am b/cde/programs/dtappbuilder/src/ab/Makefile.am
index ef119fbe5..f54178d1e 100644
--- a/cde/programs/dtappbuilder/src/ab/Makefile.am
+++ b/cde/programs/dtappbuilder/src/ab/Makefile.am
@@ -12,6 +12,10 @@ DTCODEGENCAT = NLSPATH=$(top_builddir)/programs/dtappbuilder/src/abmf/dtcodegen.
 
 DTCODEGEN = $(DTCODEGENCAT) ../abmf/dtcodegen
 
+# Due to the way dtcodegen works, especially with the -merge option, we need
+# to disable parallel builds (-j) here to avoid corrupting everything.
+.NOTPARALLEL:
+
 if BSD
 UTILLIB = -lutil
 endif