diff --git a/corepkgs/nar/nar.sh.in b/corepkgs/nar/nar.sh.in
index 9635d29f4f..11344f7fff 100644
--- a/corepkgs/nar/nar.sh.in
+++ b/corepkgs/nar/nar.sh.in
@@ -8,6 +8,8 @@ mkdir $out
 dst=$out/$(basename $path).nar.bz2
 @bindir@/nix-store --dump "$path" | @bzip2@ > $dst
 
+if test "${PIPESTATUS[0]}" != "0"; then exit 1; fi
+
 md5=$(md5sum -b $dst | cut -c1-32)
 if test $? != 0; then exit 1; fi
 echo $md5 > $out/md5