diff --git a/pkgs/build-support/release/debian-build.nix b/pkgs/build-support/release/debian-build.nix
index 5144e3169e5..85f6a73cda3 100644
--- a/pkgs/build-support/release/debian-build.nix
+++ b/pkgs/build-support/release/debian-build.nix
@@ -19,7 +19,7 @@ vmTools.runInLinuxImage (stdenv.mkDerivation (
   // removeAttrs args ["vmTools"] //
 
   {
-    name = name + "-" + diskImage.name + "-" + src.version;
+    name = name + "-" + diskImage.name + (if src ? version then "-" + src.version else "");
 
     src = if src ? outPath then src.outPath else src.path;
   
diff --git a/pkgs/build-support/release/nix-build.nix b/pkgs/build-support/release/nix-build.nix
index 142bd7bc362..0359828efeb 100644
--- a/pkgs/build-support/release/nix-build.nix
+++ b/pkgs/build-support/release/nix-build.nix
@@ -29,7 +29,7 @@ stdenv.mkDerivation (
   // args // 
 
   {
-    name = name + "-" + src.version;
+    name = name + (if src ? version then "-" + src.version else "");
   
     src = if src ? outPath then src.outPath else src.path;
 
diff --git a/pkgs/build-support/release/rpm-build.nix b/pkgs/build-support/release/rpm-build.nix
index b094732f9b7..d2d8ea65c22 100644
--- a/pkgs/build-support/release/rpm-build.nix
+++ b/pkgs/build-support/release/rpm-build.nix
@@ -11,7 +11,7 @@ vmTools.buildRPM (
   removeAttrs args ["vmTools"] //
 
   {
-    name = name + "-" + diskImage.name + "-" + src.version;
+    name = name + "-" + diskImage.name + (if src ? version then "-" + src.version else "");
 
     src = if src ? outPath then src.outPath else src.path;