diff --git a/codex-rs/windows-sandbox-rs/src/sandbox_users.rs b/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
index 13460b9444..fe47de056c 100644
--- a/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
+++ b/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
@@ -12,9 +12,12 @@ 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;
+use windows_sys::Win32::Foundation::WAIT_OBJECT_0;
+use windows_sys::Win32::Foundation::WAIT_TIMEOUT;
 use windows_sys::Win32::NetworkManagement::NetManagement::LOCALGROUP_INFO_1;
 use windows_sys::Win32::NetworkManagement::NetManagement::LOCALGROUP_MEMBERS_INFO_3;
 use windows_sys::Win32::NetworkManagement::NetManagement::NERR_Success;
@@ -33,6 +36,14 @@ 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 +87,8 @@ 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_user_profile(offline_username, &offline_password, log)?;
+    initialize_user_profile(online_username, &online_password, log)?;
     write_secrets(
         codex_home,
         offline_username,
@@ -88,6 +101,107 @@ pub fn provision_sandbox_users(
     Ok(())
 }
 
+fn initialize_user_profile(username: &str, password: &str, log: &mut File) -> Result<()> {
+    let profile_dir = PathBuf::from(format!(r"C:\Users\{username}"));
+    if profile_dir.exists() {
+        super::log_line(
+            log,
+            &format!("sandbox user profile already initialized for {username}"),
+        )?;
+        return Ok(());
+    }
+
+    let exe = r"C:\Windows\System32\cmd.exe";
+    let command = format!(r#""{exe}" /c exit 0"#);
+    let user_w = to_wide(OsStr::new(username));
+    let domain_w = to_wide(".");
+    let password_w = to_wide(OsStr::new(password));
+    let exe_w = to_wide(OsStr::new(exe));
+    let mut command_w = to_wide(command.as_str());
+    let mut startup_info: STARTUPINFOW = unsafe { std::mem::zeroed() };
+    startup_info.cb = std::mem::size_of::<STARTUPINFOW>() as u32;
+    let mut process_info: PROCESS_INFORMATION = unsafe { std::mem::zeroed() };
+
+    super::log_line(
+        log,
+        &format!("initializing sandbox user profile for {username}"),
+    )?;
+
+    let launched = unsafe {
+        CreateProcessWithLogonW(
+            user_w.as_ptr(),
+            domain_w.as_ptr(),
+            password_w.as_ptr(),
+            LOGON_WITH_PROFILE,
+            exe_w.as_ptr(),
+            command_w.as_mut_ptr(),
+            CREATE_NO_WINDOW,
+            std::ptr::null(),
+            std::ptr::null(),
+            &startup_info,
+            &mut process_info,
+        )
+    };
+    if launched == 0 {
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!(
+                "CreateProcessWithLogonW failed for {username}: {}",
+                unsafe { GetLastError() }
+            ),
+        )));
+    }
+
+    let wait_result = unsafe {
+        if process_info.hThread != 0 {
+            CloseHandle(process_info.hThread);
+        }
+        WaitForSingleObject(process_info.hProcess, INFINITE)
+    };
+
+    let mut exit_code: u32 = 1;
+    let got_exit_code = unsafe { GetExitCodeProcess(process_info.hProcess, &mut exit_code) };
+    unsafe {
+        if process_info.hProcess != 0 {
+            CloseHandle(process_info.hProcess);
+        }
+    }
+    if wait_result == WAIT_TIMEOUT {
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("profile bootstrap timed out for {username}"),
+        )));
+    }
+    if wait_result != WAIT_OBJECT_0 {
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("WaitForSingleObject failed for {username}: {wait_result}"),
+        )));
+    }
+    if got_exit_code == 0 {
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("GetExitCodeProcess failed for {username}: {}", unsafe {
+                GetLastError()
+            }),
+        )));
+    }
+    if exit_code != 0 {
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("profile bootstrap command exited with {exit_code} for {username}"),
+        )));
+    }
+    if !profile_dir.exists() {
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperUserProfileInitFailed,
+            format!("profile directory was not created for {username}"),
+        )));
+    }
+
+    Ok(())
+}
+
 pub fn ensure_sandbox_user(username: &str, password: &str, log: &mut File) -> Result<()> {
     ensure_local_user(username, password, log)?;
     ensure_local_group_member(SANDBOX_USERS_GROUP, username)?;
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",
diff --git a/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs b/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs
index 01d9e34f4a..7994cccd99 100644
--- a/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs
+++ b/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs
@@ -34,7 +34,7 @@ use windows_sys::Win32::Security::CheckTokenMembership;
 use windows_sys::Win32::Security::FreeSid;
 use windows_sys::Win32::Security::SECURITY_NT_AUTHORITY;
 
-pub const SETUP_VERSION: u32 = 5;
+pub const SETUP_VERSION: u32 = 6;
 pub const OFFLINE_USERNAME: &str = "CodexSandboxOffline";
 pub const ONLINE_USERNAME: &str = "CodexSandboxOnline";
 const ERROR_CANCELLED: u32 = 1223;