@@ -51,6 +51,29 @@ describe("getOrphanedWorktreePathForThread", () => {
     expect(result).toBeNull();
   });
 
+  it.each([
+    ["/tmp/repo/worktrees/feature-a", "/tmp/repo/worktrees/feature-a/"],
+    ["/tmp/repo/worktrees/feature-a", "/tmp/repo/worktrees/feature-a//"],
+    ["C:\\repo\\worktrees\\feature-a", "c:/repo/worktrees/feature-a/"],
+  ])("treats %s and %s as the same worktree", (targetPath, otherPath) => {
+    const threads = [
+      makeThread({ id: ThreadId.make("thread-1"), worktreePath: targetPath }),
+      makeThread({ id: ThreadId.make("thread-2"), worktreePath: otherPath }),
+    ];
+    expect(getOrphanedWorktreePathForThread(threads, ThreadId.make("thread-1"))).toBeNull();
+    expect(getOrphanedWorktreePathForThread(threads, ThreadId.make("thread-2"))).toBeNull();
+  });
+
+  it("keeps case-sensitive POSIX worktrees apart", () => {
+    const threads = [
+      makeThread({ id: ThreadId.make("thread-1"), worktreePath: "/tmp/repo/worktrees/Feature" }),
+      makeThread({ id: ThreadId.make("thread-2"), worktreePath: "/tmp/repo/worktrees/feature" }),
+    ];
+    expect(getOrphanedWorktreePathForThread(threads, ThreadId.make("thread-1"))).toBe(
+      "/tmp/repo/worktrees/Feature",
+    );
+  });
+
   it("ignores threads linked to different worktrees", () => {
     const threads = [
       makeThread({
 
@@ -1,12 +1,6 @@
-import type { ThreadShell } from "./types";
+import { normalizeProjectPathForComparison } from "@t3tools/shared/path";
 
-function normalizeWorktreePath(path: string | null): string | null {
-  const trimmed = path?.trim();
-  if (!trimmed) {
-    return null;
-  }
-  return trimmed;
-}
+import type { ThreadShell } from "./types";
 
 export function getOrphanedWorktreePathForThread(
   threads: ReadonlyArray<Pick<ThreadShell, "id" | "worktreePath">>,
@@ -17,17 +11,20 @@ export function getOrphanedWorktreePathForThread(
     return null;
   }
 
-  const targetWorktreePath = normalizeWorktreePath(targetThread.worktreePath);
+  const targetWorktreePath = targetThread.worktreePath?.trim();
   if (!targetWorktreePath) {
     return null;
   }
 
-  const isShared = threads.some((thread) => {
-    if (thread.id === threadId) {
-      return false;
-    }
-    return normalizeWorktreePath(thread.worktreePath) === targetWorktreePath;
-  });
+  // Threads can store one worktree as `/repo/wt` and `/repo/wt/`, and
+  // confirming deletion force-removes the checkout for every thread on it.
+  const targetKey = normalizeProjectPathForComparison(targetWorktreePath);
+  const isShared = threads.some(
+    (thread) =>
+      thread.id !== threadId &&
+      thread.worktreePath !== null &&
+      normalizeProjectPathForComparison(thread.worktreePath) === targetKey,
+  );
 
   return isShared ? null : targetWorktreePath;
 }