diff --git a/crates/gitbutler-project/src/controller.rs b/crates/gitbutler-project/src/controller.rs
index 353a02c8b..3a0350192 100644
--- a/crates/gitbutler-project/src/controller.rs
+++ b/crates/gitbutler-project/src/controller.rs
@@ -45,7 +45,16 @@ impl Controller {
                     bail!("can only work in main worktrees");
                 };
             }
-            Ok(_repo) => {}
+            Ok(repo) => {
+                match repo.work_dir() {
+                    None => bail!("Cannot add non-bare repositories without a workdir"),
+                    Some(wd) => {
+                        if !wd.join(".git").is_dir() {
+                            bail!("A git-repository without a `.git` directory cannot currently be added");
+                        }
+                    }
+                }
+            }
             Err(err) => {
                 return Err(anyhow::Error::from(err))
                     .context(error::Context::new("must be a Git repository"));
diff --git a/crates/gitbutler-project/tests/fixtures/various-repositories.sh b/crates/gitbutler-project/tests/fixtures/various-repositories.sh
index f4ff7135a..fade5179f 100644
--- a/crates/gitbutler-project/tests/fixtures/various-repositories.sh
+++ b/crates/gitbutler-project/tests/fixtures/various-repositories.sh
@@ -13,3 +13,8 @@ git clone simple with-submodule
   git submodule add ../submodule
   git commit -m "add submodule"
 )
+
+git clone --bare simple non-bare-without-worktree
+(cd non-bare-without-worktree
+  git config core.bare false
+)
\ No newline at end of file
diff --git a/crates/gitbutler-project/tests/projects/main.rs b/crates/gitbutler-project/tests/projects/main.rs
index 0890a67ab..c1f09e48c 100644
--- a/crates/gitbutler-project/tests/projects/main.rs
+++ b/crates/gitbutler-project/tests/projects/main.rs
@@ -23,18 +23,29 @@ mod add {
 
     mod error {
         use super::*;
+        use std::path::PathBuf;
+
+        #[test]
+        #[ignore = "Needs fix in gitoxide so it doesn't assume the parent-dir is the worktree (Git also doesn't do that)"]
+        fn non_bare_without_worktree() {
+            let (controller, _tmp) = new();
+            let root = repo_path_at("non-bare-without-worktree");
+            let err = controller.add(root).unwrap_err();
+            assert_eq!(
+                err.to_string(),
+                "Cannot add non-bare repositories without a workdir"
+            );
+        }
 
         #[test]
         fn submodule() {
             let (controller, _tmp) = new();
-            let root = gitbutler_testsupport::gix_testtools::scripted_fixture_read_only(
-                "various-repositories.sh",
-            )
-            .unwrap()
-            .join("with-submodule")
-            .join("submodule");
+            let root = repo_path_at("with-submodule").join("submodule");
             let err = controller.add(root).unwrap_err();
-            assert_eq!(err.to_string(), "TBD");
+            assert_eq!(
+                err.to_string(),
+                "A git-repository without a `.git` directory cannot currently be added"
+            );
         }
 
         #[test]
@@ -126,6 +137,14 @@ mod add {
             )
             .unwrap()
         }
+
+        fn repo_path_at(name: &str) -> PathBuf {
+            gitbutler_testsupport::gix_testtools::scripted_fixture_read_only(
+                "various-repositories.sh",
+            )
+            .unwrap()
+            .join(name)
+        }
     }
 }