diff --git a/lib/inventory/build-inventory/default.nix b/lib/inventory/build-inventory/default.nix
index 008a662a2..c51151322 100644
--- a/lib/inventory/build-inventory/default.nix
+++ b/lib/inventory/build-inventory/default.nix
@@ -98,12 +98,12 @@ let
             roleModules = builtins.map (
               role:
               let
-                path = "${clan-core.clanModules.${serviceName}}/roles/${role}.nix";
+                path = clan-core.clanModules.${serviceName} + "/roles/${role}.nix";
               in
               if builtins.pathExists path then
                 path
               else
-                throw "Module doesn't have role: '${role}'. Path: ${path} not found."
+                throw "Module doesn't have role: '${role}'. Role: ${role}.nix not found."
             ) machineRoles;
 
             roleServiceConfigs = builtins.filter (m: m != { }) (
diff --git a/lib/inventory/tests/default.nix b/lib/inventory/tests/default.nix
index 1189d7ec1..5460b477d 100644
--- a/lib/inventory/tests/default.nix
+++ b/lib/inventory/tests/default.nix
@@ -42,13 +42,13 @@ in
 
       expected = {
         server_imports = [
-          "${clan-core.clanModules.borgbackup}/roles/server.nix"
+          (clan-core.clanModules.borgbackup + "/roles/server.nix")
         ];
         client_1_imports = [
-          "${clan-core.clanModules.borgbackup}/roles/client.nix"
+          (clan-core.clanModules.borgbackup + "/roles/client.nix")
         ];
         client_2_imports = [
-          "${clan-core.clanModules.borgbackup}/roles/client.nix"
+          (clan-core.clanModules.borgbackup + "/roles/client.nix")
         ];
       };
     };
@@ -114,8 +114,8 @@ in
       };
       expected = {
         machine_1_imports = [
-          "${clan-core.clanModules.borgbackup}/roles/client.nix"
-          "${clan-core.clanModules.borgbackup}/roles/server.nix"
+          (clan-core.clanModules.borgbackup + "/roles/client.nix")
+          (clan-core.clanModules.borgbackup + "/roles/server.nix")
         ];
       };
     };