diff --git a/morph/grid/local/Vagrantfile b/morph/grid/local/Vagrantfile
index 7c20fddda1516d31abd65c9850abaf7619ce8030..81dec21ee701d761b4347f11df43398d78d4b528 100644
--- a/morph/grid/local/Vagrantfile
+++ b/morph/grid/local/Vagrantfile
@@ -33,6 +33,7 @@ Vagrant.configure("2") do |config|
   end
 
   # To make the VMs assign the static IPs to the network interfaces we need a rebuild:
+  config.vm.provision "shell", inline: "echo '{nix.trustedUsers = [ \"@wheel\" \"root\" \"vagrant\" ];}' > /etc/nixos/custom-configuration.nix"
   config.vm.provision "shell", inline: "nixos-rebuild switch"
 
   config.trigger.after :up do |trigger|