diff --git a/src/features/team-mode/team-registry/paths.test.ts b/src/features/team-mode/team-registry/paths.test.ts
index 1fd80f4bb..2cf1cc575 100644
--- a/src/features/team-mode/team-registry/paths.test.ts
+++ b/src/features/team-mode/team-registry/paths.test.ts
@@ -117,4 +117,53 @@ describe("paths", () => {
       expect(directoryStat.mode & 0o777).toBe(0o700)
     }
   })
+
+  test("ensureBaseDirs swallows EPERM from chmod and logs a warning instead of aborting team-mode init", async () => {
+    // given: directories exist with permissive mode that chmod cannot tighten
+    // (mirrors macOS network mount / non-owner / SIP cases reported in #4023).
+    const baseDir = path.join(tmpdir(), `omo-test-eperm-${randomUUID()}`)
+    temporaryDirectories.push(baseDir)
+    await mkdir(baseDir, { recursive: true })
+    await mkdir(path.join(baseDir, "teams"), { recursive: true })
+    await mkdir(path.join(baseDir, "runtime"), { recursive: true })
+    await mkdir(path.join(baseDir, "worktrees"), { recursive: true })
+
+    const realFs = await import("node:fs/promises")
+    let chmodCalls = 0
+    mock.module("node:fs/promises", () => ({
+      ...realFs,
+      chmod: async (target: string) => {
+        chmodCalls += 1
+        const eperm = Object.assign(new Error(`EPERM: operation not permitted, chmod '${target}'`), {
+          code: "EPERM",
+          syscall: "chmod",
+          path: target,
+          errno: -1,
+        })
+        throw eperm
+      },
+    }))
+
+    const { ensureBaseDirs: ensureBaseDirsWithMockedChmod } = await import("./paths")
+    logCalls.splice(0)
+
+    // when
+    let thrown: unknown = null
+    try {
+      await ensureBaseDirsWithMockedChmod(baseDir)
+    } catch (error) {
+      thrown = error
+    }
+
+    // then: function does not throw, EPERM was reached, and one warning was logged.
+    expect(thrown).toBeNull()
+    expect(chmodCalls).toBeGreaterThan(0)
+    const warnings = logCalls.filter(([message]) =>
+      message === "team-mode: chmod refused on base directory; continuing with existing permissions"
+    )
+    expect(warnings.length).toBeGreaterThan(0)
+    const firstWarning = warnings[0]?.[1] as { code?: string; path?: string } | undefined
+    expect(firstWarning?.code).toBe("EPERM")
+    expect(firstWarning?.path).toContain(baseDir)
+  })
 })
diff --git a/src/features/team-mode/team-registry/paths.ts b/src/features/team-mode/team-registry/paths.ts
index c80032575..b41b1ed7e 100644
--- a/src/features/team-mode/team-registry/paths.ts
+++ b/src/features/team-mode/team-registry/paths.ts
@@ -100,6 +100,23 @@ export async function discoverTeamSpecs(
   return discoveredTeamSpecs
 }
 
+async function safeChmod(directoryPath: string, mode: number): Promise<void> {
+  try {
+    await chmod(directoryPath, mode)
+  } catch (error) {
+    const errnoError = error as NodeJS.ErrnoException
+    if (errnoError?.code === "EPERM" || errnoError?.code === "ENOTSUP" || errnoError?.code === "EINVAL") {
+      log("team-mode: chmod refused on base directory; continuing with existing permissions", {
+        path: directoryPath,
+        code: errnoError.code,
+        syscall: errnoError.syscall,
+      })
+      return
+    }
+    throw error
+  }
+}
+
 export async function ensureBaseDirs(baseDir: string): Promise<void> {
   const directories = [
     baseDir,
@@ -110,13 +127,13 @@ export async function ensureBaseDirs(baseDir: string): Promise<void> {
 
   for (const directoryPath of directories) {
     await mkdir(directoryPath, { recursive: true, mode: 0o700 })
-    await chmod(directoryPath, 0o700)
+    await safeChmod(directoryPath, 0o700)
   }
 
   await Promise.all(directories.map(async (directoryPath) => {
     const directoryStat = await stat(directoryPath)
     if ((directoryStat.mode & 0o777) !== 0o700) {
-      await chmod(directoryPath, 0o700)
+      await safeChmod(directoryPath, 0o700)
     }
   }))
 }