diff --git a/src/ClaudeDo.Installer/Steps/WriteInstallManifestStep.cs b/src/ClaudeDo.Installer/Steps/WriteInstallManifestStep.cs
index 32ae104..83cfda8 100644
--- a/src/ClaudeDo.Installer/Steps/WriteInstallManifestStep.cs
+++ b/src/ClaudeDo.Installer/Steps/WriteInstallManifestStep.cs
@@ -12,14 +12,21 @@ public sealed class WriteInstallManifestStep : IInstallStep
         if (string.IsNullOrWhiteSpace(ctx.InstalledVersion))
             return Task.FromResult(StepResult.Fail("Installed version is not set — DownloadAndExtractStep must run first."));
 
-        var manifest = new InstallManifest(
-            Version: ctx.InstalledVersion!,
-            InstallDir: ctx.InstallDirectory,
-            WorkerDir: Path.Combine(ctx.InstallDirectory, "worker"),
-            InstalledAt: DateTimeOffset.UtcNow);
+        try
+        {
+            var manifest = new InstallManifest(
+                Version: ctx.InstalledVersion,
+                InstallDir: ctx.InstallDirectory,
+                WorkerDir: Path.Combine(ctx.InstallDirectory, "worker"),
+                InstalledAt: DateTimeOffset.UtcNow);
 
-        InstallManifestStore.Write(ctx.InstallDirectory, manifest);
-        progress.Report($"Wrote {InstallManifestStore.ManifestPath(ctx.InstallDirectory)}");
-        return Task.FromResult(StepResult.Ok());
+            InstallManifestStore.Write(ctx.InstallDirectory, manifest);
+            progress.Report($"Wrote {InstallManifestStore.ManifestPath(ctx.InstallDirectory)}");
+            return Task.FromResult(StepResult.Ok());
+        }
+        catch (Exception ex)
+        {
+            return Task.FromResult(StepResult.Fail(ex.Message));
+        }
     }
 }