diff --git a/apps/code/src/main/services/archive/service.integration.test.ts b/apps/code/src/main/services/archive/service.integration.test.ts
index f5f06d69b..50f7e05b7 100644
--- a/apps/code/src/main/services/archive/service.integration.test.ts
+++ b/apps/code/src/main/services/archive/service.integration.test.ts
@@ -360,6 +360,20 @@ describe("ArchiveService integration", () => {
         expect(archived.checkpointId).toBeTruthy();
         expect(await pathExists(legacyPath)).toBe(false);
       }));
+
+    it("archive succeeds when worktree was deleted externally", () =>
+      withTestContext({}, async (ctx) => {
+        const { worktreePath } = await ctx.setupWorktree("detached");
+
+        await fs.rm(worktreePath, { recursive: true, force: true });
+        expect(await pathExists(worktreePath)).toBe(false);
+
+        const archived = await ctx.service.archiveTask(ctx.archiveInput());
+
+        expect(archived.checkpointId).toBeNull();
+        expect(archived.branchName).toBeNull();
+        expect(ctx.archiveRepo.findAll()).toHaveLength(1);
+      }));
   });
 
   describe("local/cloud mode", () => {
diff --git a/apps/code/src/main/services/archive/service.ts b/apps/code/src/main/services/archive/service.ts
index 2a302fe9a..06c98e29a 100644
--- a/apps/code/src/main/services/archive/service.ts
+++ b/apps/code/src/main/services/archive/service.ts
@@ -1,6 +1,7 @@
 import fs from "node:fs/promises";
 import path from "node:path";
 import { createGitClient } from "@posthog/git/client";
+import { isGitRepository } from "@posthog/git/queries";
 import {
   CaptureCheckpointSaga,
   deleteCheckpoint,
@@ -173,31 +174,47 @@ export class ArchiveService {
 
       if (workspace.mode === "worktree" && worktree) {
         const worktreePath = worktree.path;
-
-        const actualBranch = await this.getCurrentBranchName(worktreePath);
-        if (actualBranch && actualBranch !== "HEAD") {
-          archivedTask.branchName = actualBranch;
-        }
-
-        await step(
-          async () => {
-            if (!archivedTask.checkpointId) {
-              throw new Error("checkpointId must be set for worktree mode");
-            }
-            await this.captureWorktreeCheckpoint(
-              folderPath,
-              worktreePath,
-              archivedTask.checkpointId,
+        const worktreeIsValid = await isGitRepository(worktreePath).catch(
+          (error) => {
+            log.warn(
+              `Failed to check worktree at ${worktreePath}; treating as invalid`,
+              { error },
             );
-          },
-          async () => {
-            if (archivedTask.checkpointId) {
-              const git = createGitClient(folderPath);
-              await deleteCheckpoint(git, archivedTask.checkpointId);
-            }
+            return false;
           },
         );
 
+        if (!worktreeIsValid) {
+          log.warn(
+            `Worktree at ${worktreePath} is missing or not a git repository; skipping checkpoint capture`,
+          );
+          archivedTask.checkpointId = null;
+        } else {
+          const actualBranch = await this.getCurrentBranchName(worktreePath);
+          if (actualBranch && actualBranch !== "HEAD") {
+            archivedTask.branchName = actualBranch;
+          }
+
+          await step(
+            async () => {
+              if (!archivedTask.checkpointId) {
+                throw new Error("checkpointId must be set for worktree mode");
+              }
+              await this.captureWorktreeCheckpoint(
+                folderPath,
+                worktreePath,
+                archivedTask.checkpointId,
+              );
+            },
+            async () => {
+              if (archivedTask.checkpointId) {
+                const git = createGitClient(folderPath);
+                await deleteCheckpoint(git, archivedTask.checkpointId);
+              }
+            },
+          );
+        }
+
         await step(
           async () => {
             await this.agentService.cancelSessionsByTaskId(taskId);