diff --git a/modules/environment/login/login-inner.nix b/modules/environment/login/login-inner.nix
index cb929ddb..53d9f322 100644
--- a/modules/environment/login/login-inner.nix
+++ b/modules/environment/login/login-inner.nix
@@ -144,6 +144,11 @@ writeText "login-inner" ''
   usershell="${config.user.shell}"
   if [ "$#" -gt 0 ]; then  # if script is not called from within Nix-on-Droid app
     exec /usr/bin/env "$@"
+  elif [ -d "$usershell" ]; then
+    echo "Cannot execute shell '${config.user.shell}', it is a directory."
+    echo "Unlike nixos you should point `user.shell` to the exact binary."
+    echo "Falling back to bash"
+    exec -l bash
   elif [ -x "$usershell" ]; then
     exec -a "-''${usershell##*/}" "$usershell"
   else