diff --git a/mache/spack/compy_intel_impi.yaml b/mache/spack/compy_intel_impi.yaml
index ac2671e..9ec283b 100644
--- a/mache/spack/compy_intel_impi.yaml
+++ b/mache/spack/compy_intel_impi.yaml
@@ -129,7 +129,7 @@ spack:
       buildable: false
     netcdf-c:
       externals:
-      - spec: netcdf-c~mpi~parallel-netcdf@4.6.3
+      - spec: netcdf-c+mpi~parallel-netcdf@4.6.3
         prefix: /share/apps/netcdf/4.6.3/intel/20.0.0
         modules:
         - netcdf/4.6.3