diff --git a/aider/repo.py b/aider/repo.py
index 92b5e3bf5b8..e4ced4ae3a1 100644
--- a/aider/repo.py
+++ b/aider/repo.py
@@ -123,6 +123,12 @@ def __init__(
 
         # https://github.com/gitpython-developers/GitPython/issues/427
         self.repo = git.Repo(repo_paths.pop(), odbt=git.GitDB)
+
+        if not self.repo.working_tree_dir:
+            raise FileNotFoundError(
+                "The git repo does not seem to have a working tree?"
+            )
+
         self.root = utils.safe_abs_path(self.repo.working_tree_dir)
 
         if aider_ignore_file:
diff --git a/tests/basic/test_repo.py b/tests/basic/test_repo.py
index 71ba9479830..610ea9631fb 100644
--- a/tests/basic/test_repo.py
+++ b/tests/basic/test_repo.py
@@ -714,3 +714,10 @@ def test_get_commit_message_uses_system_prompt_prefix(self, mock_send):
                 system_msg_content.startswith(prefix),
                 "system_prompt_prefix should be prepended to the system prompt",
             )
+
+    def test_bare_repo_raises_file_not_found(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            bare_path = Path(tmpdir) / "bare.git"
+            git.Repo.init(str(bare_path), bare=True)
+            with self.assertRaises(FileNotFoundError):
+                GitRepo(InputOutput(), None, str(bare_path))