diff --git a/frontend/js/app.js b/frontend/js/app.js
index 40a1e94..8c91271 100644
--- a/frontend/js/app.js
+++ b/frontend/js/app.js
@@ -121,6 +121,21 @@ const EMPTY_DIFF_ICON = lucideIcon("FileDiff", { size: 44, strokeWidth: 1.6 });
 const EMPTY_FILE_ICON = lucideIcon("File", { size: 44, strokeWidth: 1.6 });
 const EMPTY_REPO_ICON = lucideIcon("FolderGit2", { size: 44, strokeWidth: 1.6 });
 
+function errorMessage(error, fallback = "Unknown error.") {
+  if (typeof error === "string" && error.trim()) return error;
+  if (error instanceof Error && error.message) return error.message;
+  if (error && typeof error === "object") {
+    if (typeof error.message === "string" && error.message.trim()) return error.message;
+    try {
+      const serialized = JSON.stringify(error);
+      if (serialized && serialized !== "{}") return serialized;
+    } catch {
+      // Fall through to the generic fallback.
+    }
+  }
+  return fallback;
+}
+
 function currentPlatform() {
   const platform = navigator.userAgentData?.platform || navigator.platform || "";
   const userAgent = navigator.userAgent || "";
@@ -1670,7 +1685,7 @@ function bindServerFormEvents(existingServer = null) {
       render();
       openServerForm(existingServer?.id || null);
     } catch (error) {
-      serverTestResult = `Connection test failed: ${error.message}`;
+      serverTestResult = `Connection test failed: ${errorMessage(error)}`;
       render();
       openServerForm(existingServer?.id || null);
     }
@@ -1733,7 +1748,7 @@ async function loadRepositories() {
     currentUserLogin = user.login || "";
     repositories = repos;
   } catch (error) {
-    settingsNotice = `Using mock repositories. API fetch failed: ${error.message}`;
+    settingsNotice = `Using mock repositories. API fetch failed: ${errorMessage(error)}`;
     currentUserLogin = "alice";
     repositories = [...mockRepos];
   }
@@ -1811,7 +1826,7 @@ async function refreshBranches() {
   try {
     state.branches.items = await listLocalRepoBranches(state.selectedRepoPath, selectedGitPath());
   } catch (error) {
-    state.branches.error = `Unable to load branches: ${error.message}`;
+    state.branches.error = `Unable to load branches: ${errorMessage(error)}`;
   } finally {
     state.branches.loading = false;
     render();
@@ -1851,7 +1866,7 @@ async function refreshWorkingTree() {
       await loadSelectedDiff(tree.selectedPath, false);
     }
   } catch (error) {
-    tree.error = `Unable to load changes: ${error.message}`;
+    tree.error = `Unable to load changes: ${errorMessage(error)}`;
   } finally {
     tree.loading = false;
     render();
@@ -1905,7 +1920,7 @@ async function refreshSyncState({ silent = false } = {}) {
     state.workingTree.behind = sync.behind;
   } catch (error) {
     if (getState().selectedRepoPath !== repoPath) return;
-    sync.error = error.message;
+    sync.error = errorMessage(error);
   } finally {
     if (getState().selectedRepoPath === repoPath) {
       sync.loading = false;
@@ -1927,7 +1942,7 @@ async function loadSelectedDiff(path, shouldRender = true) {
     tree.selectedDiff = await getFileDiff(state.selectedRepoPath, file.path, file.status, selectedGitPath());
   } catch (error) {
     tree.selectedDiff = null;
-    tree.diffError = `Unable to load diff: ${error.message}`;
+    tree.diffError = `Unable to load diff: ${errorMessage(error)}`;
   } finally {
     tree.diffLoading = false;
     if (shouldRender) render();
@@ -1956,7 +1971,7 @@ async function refreshHistory() {
       await loadCommitDetail(history.selectedHash, false);
     }
   } catch (error) {
-    history.error = `Unable to load history: ${error.message}`;
+    history.error = `Unable to load history: ${errorMessage(error)}`;
   } finally {
     history.loading = false;
     render();
@@ -1972,7 +1987,7 @@ async function loadCommitDetail(hash, shouldRender = true) {
   try {
     state.history.selectedCommit = await getCommitDetail(state.selectedRepoPath, hash, selectedGitPath());
   } catch (error) {
-    state.history.error = `Unable to load commit: ${error.message}`;
+    state.history.error = `Unable to load commit: ${errorMessage(error)}`;
   } finally {
     if (shouldRender) render();
   }
@@ -2020,7 +2035,7 @@ async function scanForLocalRepos() {
     }
   } catch (error) {
     state.localRepoScanResults = [];
-    state.localRepoScanError = `Repo scan failed: ${error.message}`;
+    state.localRepoScanError = `Repo scan failed: ${errorMessage(error)}`;
   } finally {
     state.localRepoScanLoading = false;
     render();
@@ -2059,7 +2074,7 @@ async function loadViewerPath(path = "") {
     render();
     await autoLoadReadme();
   } catch (error) {
-    viewer.error = `Unable to load repository contents: ${error.message}`;
+    viewer.error = `Unable to load repository contents: ${errorMessage(error)}`;
     viewer.loading = false;
     render();
   }
@@ -2108,7 +2123,7 @@ async function openViewerFile(path) {
       };
     }
   } catch (error) {
-    viewer.error = `Unable to preview file: ${error.message}`;
+    viewer.error = `Unable to preview file: ${errorMessage(error)}`;
   } finally {
     viewer.loading = false;
     render();
@@ -2146,7 +2161,7 @@ async function openRemoteViewer(repo) {
     await loadViewerPath("");
   } catch (error) {
     viewer.loading = false;
-    viewer.error = `Unable to open repository viewer: ${error.message}`;
+    viewer.error = `Unable to open repository viewer: ${errorMessage(error)}`;
     render();
   }
 }
@@ -2186,7 +2201,7 @@ async function openLocalViewer() {
     await loadViewerPath("");
   } catch (error) {
     viewer.loading = false;
-    viewer.error = `Unable to open local viewer: ${error.message}`;
+    viewer.error = `Unable to open local viewer: ${errorMessage(error)}`;
     render();
   }
 }
@@ -2201,7 +2216,7 @@ async function refreshInstalledIdes() {
     state.installedIdes = await scanInstalledIdes();
   } catch (error) {
     state.installedIdes = [];
-    state.installedIdeScanError = `Unable to scan installed IDEs: ${error.message}`;
+    state.installedIdeScanError = `Unable to scan installed IDEs: ${errorMessage(error)}`;
   } finally {
     state.installedIdeScanLoading = false;
     render();
@@ -2220,7 +2235,7 @@ async function openSelectedRepoInFileExplorer() {
     await openInFileExplorer(state.selectedRepoPath);
     gitOutput = `Opened in File Explorer:\n${state.selectedRepoPath}`;
   } catch (error) {
-    gitOutput = `Open in File Explorer failed: ${error.message}`;
+    gitOutput = `Open in File Explorer failed: ${errorMessage(error)}`;
   } finally {
     utilityMenuOpen = false;
     render();
@@ -2240,7 +2255,7 @@ async function openSelectedRepoInCodeEditor() {
     await openInExternalEditor(state.selectedRepoPath, editorCommand);
     gitOutput = `Opened in Code Editor with "${editorCommand}":\n${state.selectedRepoPath}`;
   } catch (error) {
-    gitOutput = `Open in Code Editor failed: ${error.message}`;
+    gitOutput = `Open in Code Editor failed: ${errorMessage(error)}`;
   } finally {
     utilityMenuOpen = false;
     render();
@@ -2262,8 +2277,9 @@ async function runRepoCommand(actionName, runner, operation = "") {
     const result = await runner();
     gitOutput = `${actionName}: ${result.command}\n\n${result.stdout || "(no stdout)"}\n${result.stderr ? `\n${result.stderr}` : ""}`;
   } catch (error) {
-    gitOutput = `${actionName} failed: ${error.message}`;
-    state.sync.error = error.message;
+    const message = errorMessage(error);
+    gitOutput = `${actionName} failed: ${message}`;
+    state.sync.error = message;
   } finally {
     state.sync.operation = "";
   }
@@ -2550,7 +2566,7 @@ function bindDashboardEvents() {
       state.commitDescription = "";
       await refreshRepoData();
     } catch (error) {
-      gitOutput = `Commit failed: ${error.message}`;
+      gitOutput = `Commit failed: ${errorMessage(error)}`;
       render();
     }
   });
@@ -2576,7 +2592,7 @@ function bindDashboardEvents() {
         state.branches.menuOpen = false;
         await refreshRepoData();
       } catch (error) {
-        gitOutput = `Branch switch failed: ${error.message}`;
+        gitOutput = `Branch switch failed: ${errorMessage(error)}`;
         state.branches.menuOpen = false;
         render();
       }
@@ -2616,7 +2632,7 @@ function bindDashboardEvents() {
       Object.assign(dialog, { mode: "", target: "", value: "", error: "" });
       await refreshRepoData();
     } catch (error) {
-      dialog.error = error.message;
+      dialog.error = errorMessage(error);
       render();
     }
   });
@@ -2649,7 +2665,7 @@ function bindDashboardEvents() {
     try {
       selectedDirectory = await browseDirectory(state.settings.defaultCloneDirectory || "");
     } catch (error) {
-      gitOutput = `Could not open folder picker: ${error.message}`;
+      gitOutput = `Could not open folder picker: ${errorMessage(error)}`;
       render();
       return;
     }
@@ -2682,7 +2698,7 @@ function bindDashboardEvents() {
       activeView = "changes";
       await refreshRepoData();
     } catch (error) {
-      gitOutput = `Clone failed: ${error.message}`;
+      gitOutput = `Clone failed: ${errorMessage(error)}`;
     }
     render();
   });
@@ -2698,7 +2714,7 @@ function bindDashboardEvents() {
     try {
       selectedApplication = await browseApplication(currentValue);
     } catch (error) {
-      settingsNotice = `Could not open application picker: ${error.message}`;
+      settingsNotice = `Could not open application picker: ${errorMessage(error)}`;
       render();
       return;
     }