diff --git a/win_installer/src/wim.rs b/win_installer/src/wim.rs
index 9a43f5c..cb44c22 100644
--- a/win_installer/src/wim.rs
+++ b/win_installer/src/wim.rs
@@ -273,7 +273,10 @@ pub fn parse_wim_file(wim_file: &str, is_setup: bool) -> std::io::Result<WimFile
                     }
                     // Append image to list
                     if image.build.is_empty() {
-                        image.build.push_str("-14");
+                        image.build.push('?');
+                    }
+                    if image.spbuild.is_empty() {
+                        image.spbuild.push('?');
                     }
                     if !image.name.is_empty() && !image.index.is_empty() {
                         wim_images.push(image.clone());