diff --git a/codex-rs/windows-sandbox-rs/src/sandbox_users.rs b/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
index 13460b9444..ff20d9fd95 100644
--- a/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
+++ b/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
@@ -12,6 +12,7 @@ use std::ffi::c_void;
 use std::fs::File;
 use std::path::Path;
 use std::path::PathBuf;
+use windows_sys::Win32::Foundation::CloseHandle;
 use windows_sys::Win32::Foundation::ERROR_INSUFFICIENT_BUFFER;
 use windows_sys::Win32::Foundation::GetLastError;
 use windows_sys::Win32::Foundation::LocalFree;
@@ -33,6 +34,14 @@ use windows_sys::Win32::Security::GetLengthSid;
 use windows_sys::Win32::Security::LookupAccountNameW;
 use windows_sys::Win32::Security::LookupAccountSidW;
 use windows_sys::Win32::Security::SID_NAME_USE;
+use windows_sys::Win32::System::Threading::CREATE_NO_WINDOW;
+use windows_sys::Win32::System::Threading::CreateProcessWithLogonW;
+use windows_sys::Win32::System::Threading::GetExitCodeProcess;
+use windows_sys::Win32::System::Threading::INFINITE;
+use windows_sys::Win32::System::Threading::LOGON_WITH_PROFILE;
+use windows_sys::Win32::System::Threading::PROCESS_INFORMATION;
+use windows_sys::Win32::System::Threading::STARTUPINFOW;
+use windows_sys::Win32::System::Threading::WaitForSingleObject;
 
 use codex_windows_sandbox::SETUP_VERSION;
 use codex_windows_sandbox::SetupErrorCode;
@@ -76,6 +85,8 @@ pub fn provision_sandbox_users(
     let online_password = random_password();
     ensure_sandbox_user(offline_username, &offline_password, log)?;
     ensure_sandbox_user(online_username, &online_password, log)?;
+    initialize_sandbox_user_profile(offline_username, &offline_password, log)?;
+    initialize_sandbox_user_profile(online_username, &online_password, log)?;
     write_secrets(
         codex_home,
         offline_username,
@@ -94,6 +105,105 @@ pub fn ensure_sandbox_user(username: &str, password: &str, log: &mut File) -> Re
     Ok(())
 }
 
+fn initialize_sandbox_user_profile(username: &str, password: &str, log: &mut File) -> Result<()> {
+    let system_root = std::env::var("SystemRoot").unwrap_or_else(|_| r"C:\Windows".to_string());
+    let system32 = PathBuf::from(system_root).join("System32");
+    let cmd_path = system32.join("cmd.exe");
+    let cmdline = format!("{} /c exit 0", quote_for_command_line(&cmd_path));
+    let mut cmdline_w = to_wide(cmdline);
+    let user_w = to_wide(username);
+    let domain_w = to_wide(".");
+    let password_w = to_wide(password);
+    let cmd_path_w = to_wide(cmd_path.as_os_str());
+    let cwd_w = to_wide(system32.as_os_str());
+    let mut si: STARTUPINFOW = unsafe { std::mem::zeroed() };
+    si.cb = std::mem::size_of::<STARTUPINFOW>() as u32;
+    let mut pi: PROCESS_INFORMATION = unsafe { std::mem::zeroed() };
+
+    super::log_line(
+        log,
+        &format!("bootstrapping sandbox user profile for {username}"),
+    )?;
+
+    let spawn_res = unsafe {
+        CreateProcessWithLogonW(
+            user_w.as_ptr(),
+            domain_w.as_ptr(),
+            password_w.as_ptr(),
+            LOGON_WITH_PROFILE,
+            cmd_path_w.as_ptr(),
+            cmdline_w.as_mut_ptr(),
+            CREATE_NO_WINDOW,
+            std::ptr::null(),
+            cwd_w.as_ptr(),
+            &si,
+            &mut pi,
+        )
+    };
+    if spawn_res == 0 {
+        let err = unsafe { GetLastError() };
+        super::log_line(
+            log,
+            &format!("profile bootstrap failed for {username}: {err}"),
+        )?;
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("CreateProcessWithLogonW failed for {username}: {err}"),
+        )));
+    }
+
+    let wait_status = unsafe { WaitForSingleObject(pi.hProcess, INFINITE) };
+    let mut exit_code = 0u32;
+    let exit_status = unsafe { GetExitCodeProcess(pi.hProcess, &mut exit_code) };
+    unsafe {
+        if pi.hThread != 0 {
+            CloseHandle(pi.hThread);
+        }
+        if pi.hProcess != 0 {
+            CloseHandle(pi.hProcess);
+        }
+    }
+
+    if wait_status != 0 {
+        super::log_line(
+            log,
+            &format!("profile bootstrap wait failed for {username}: {wait_status}"),
+        )?;
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("WaitForSingleObject failed for {username}: {wait_status}"),
+        )));
+    }
+    if exit_status == 0 {
+        let err = unsafe { GetLastError() };
+        super::log_line(
+            log,
+            &format!("profile bootstrap exit-code read failed for {username}: {err}"),
+        )?;
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("GetExitCodeProcess failed for {username}: {err}"),
+        )));
+    }
+    if exit_code != 0 {
+        super::log_line(
+            log,
+            &format!("profile bootstrap exited non-zero for {username}: {exit_code}"),
+        )?;
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("profile bootstrap exited {exit_code} for {username}"),
+        )));
+    }
+
+    super::log_line(log, &format!("profile bootstrap succeeded for {username}"))?;
+    Ok(())
+}
+
+fn quote_for_command_line(path: &Path) -> String {
+    format!("\"{}\"", path.display())
+}
+
 pub fn ensure_local_user(name: &str, password: &str, log: &mut File) -> Result<()> {
     let name_w = to_wide(OsStr::new(name));
     let pwd_w = to_wide(OsStr::new(password));
diff --git a/codex-rs/windows-sandbox-rs/src/setup_error.rs b/codex-rs/windows-sandbox-rs/src/setup_error.rs
index 64e618ace1..8414f8e5fb 100644
--- a/codex-rs/windows-sandbox-rs/src/setup_error.rs
+++ b/codex-rs/windows-sandbox-rs/src/setup_error.rs
@@ -42,6 +42,8 @@ pub enum SetupErrorCode {
     HelperUsersGroupCreateFailed,
     /// Helper failed to create or update a sandbox user account.
     HelperUserCreateOrUpdateFailed,
+    /// Helper failed to initialize a sandbox user profile.
+    HelperUserProfileInitFailed,
     /// Helper failed to protect user passwords with DPAPI.
     HelperDpapiProtectFailed,
     /// Helper failed to write the sandbox users secrets file.
@@ -84,6 +86,7 @@ impl SetupErrorCode {
             Self::HelperUserProvisionFailed => "helper_user_provision_failed",
             Self::HelperUsersGroupCreateFailed => "helper_users_group_create_failed",
             Self::HelperUserCreateOrUpdateFailed => "helper_user_create_or_update_failed",
+            Self::HelperUserProfileInitFailed => "helper_user_profile_init_failed",
             Self::HelperDpapiProtectFailed => "helper_dpapi_protect_failed",
             Self::HelperUsersFileWriteFailed => "helper_users_file_write_failed",
             Self::HelperSetupMarkerWriteFailed => "helper_setup_marker_write_failed",