diff --git a/src/resources/extensions/gsd/repo-identity.ts b/src/resources/extensions/gsd/repo-identity.ts
index e704c4f48..d3133c3d6 100644
--- a/src/resources/extensions/gsd/repo-identity.ts
+++ b/src/resources/extensions/gsd/repo-identity.ts
@@ -164,7 +164,8 @@ function getRemoteUrl(basePath: string): string {
  */
 function canonicalizeExistingPath(path: string): string {
   try {
-    return realpathSync(path);
+    // Use native realpath on Windows to resolve 8.3 short paths (e.g. RUNNER~1)
+    return process.platform === "win32" ? realpathSync.native(path) : realpathSync(path);
   } catch {
     return resolve(path);
   }