diff --git a/pkgs/os-specific/linux/firejail/default.nix b/pkgs/os-specific/linux/firejail/default.nix
index 0e982d54a9e0..672ee823fe8e 100644
--- a/pkgs/os-specific/linux/firejail/default.nix
+++ b/pkgs/os-specific/linux/firejail/default.nix
@@ -43,7 +43,9 @@ stdenv.mkDerivation {
     sed -E -e 's@^include (.*)(/firejail/.*.local)$@include /etc\2@g' -i $out/etc/firejail/*.profile
   '';
 
-  enableParallelBuilding = true;
+  # At high parallelism, the build sometimes fails with:
+  # bash: src/fsec-optimize/fsec-optimize: No such file or directory
+  enableParallelBuilding = false;
 
   meta = {
     inherit (s) version;