diff --git a/spack.yaml b/spack.yaml
index cf5d26ef2bc8a305c54aee68d3a4224941af2121..8451670d07c2df95a98d7a08075e1c364d6741ec 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -1,7 +1,7 @@
 spack:
   specs:
-    - nest +python +gsl +mpi ^py-scipy@:1.6.999 %gcc@10.3.0
+    #- nest +python +gsl +mpi ^py-scipy@:1.6.999 %gcc@10.3.0
     - arbor +mpi %gcc@10.3.0
-    - neuron +mpi %gcc@10.3.0
+    #- neuron +mpi %gcc@10.3.0
     # BrainScaleS (plus some constraining)
     - visionary-dls-core ^py-setuptools-scm+toml ^python@3.8.0:3.8.999 ^binutils+ld ^py-astroid@2.5.6:2.6.999 ^py-scipy@:1.6.999 %gcc@10.3.0