diff --git a/nixos/modules/security/pam.nix b/nixos/modules/security/pam.nix
index 61b39cb8e2cf..c10449454c50 100644
--- a/nixos/modules/security/pam.nix
+++ b/nixos/modules/security/pam.nix
@@ -2298,7 +2298,7 @@ in
       ++ lib.optionals config.security.pam.enableFscrypt [ pkgs.fscrypt-experimental ]
       ++ lib.optionals config.security.pam.u2f.enable [ pkgs.pam_u2f ];
 
-    boot.supportedFilesystems = lib.optionals config.security.pam.enableEcryptfs [ "ecryptfs" ];
+    boot.supportedFilesystems = lib.mkIf config.security.pam.enableEcryptfs [ "ecryptfs" ];
 
     security.wrappers = {
       unix_chkpwd = {