Login Timestamp Error or Bad Timestamp Error (40105) on a Company Laptop 

One of our users reported that their company laptop displayed a Login Timestamp Error (also known as Bad Timestamp Error 40105) while attempting to sign in.

In most enterprise environments, this error occurs because the laptop's date and time are not synchronized with the organization's authentication server.


This commonly happens when:

• The laptop has been disconnected from the company network for several days.
• The device has not connected to the corporate VPN.
• The BIOS date and time are incorrect.
• Windows Time service is not running.

Fortunately, this issue can usually be resolved within a few minutes.

Table of Contents

1. What is Login Timestamp Error (40105)?
2. Why Does This Error Occur?
3. Solution 1: Restart Windows Time Service
4. Solution 2: Correct Date & Time from BIOS
5. How Windows Time Synchronization Works
6. Additional Troubleshooting
7. Frequently Asked Questions
8. Conclusion

What is Login Timestamp Error (40105)?

The Login Timestamp Error (40105) is an authentication error that occurs when the system time on your laptop differs significantly from the company's authentication server. Error 40105

Most organizations use technologies such as Active Directory, Kerberos Authentication, or Single Sign-On (SSO), which rely on accurate timestamps to validate login requests.

If the time difference exceeds the allowed limit, authentication fails.

Why Does This Error Occur?

The company's authentication server verifies your computer's system time before allowing access.

If your laptop clock is incorrect, Windows sends an invalid timestamp during authentication, causing the login request to fail. Windows Time Service


Common causes include:

• Incorrect BIOS date and time
• Windows Time service stopped
• Laptop disconnected from VPN for a long period
• CMOS battery issue
• Failed time synchronization with the domain controller

Quick Fix 1: Restart Windows Time Service

If you're able to sign in to Windows, restart the Windows Time service.

Steps

• Press Win + R
• Type services.msc
• Press Enter
• Locate Windows Time
• Right-click it
• Select Restart

If the service is stopped, click Start.
This forces Windows to begin time synchronization again.
Tip: You can also restart the service from Command Prompt (Run as Administrator):

• net stop w32time
• net start w32time

Quick Fix 2: Correct the Date and Time from BIOS (UEFI)

If Windows displays an incorrect time before connecting to the network, verify the BIOS clock. Login Timestamp Error 40105

Steps

Restart the laptop.
Enter BIOS/UEFI (usually F2, F10, F12, Delete, or Esc).
Navigate to Date & Time.
Update the correct date and time.
Press F10 to save.
Restart Windows.

Note: BIOS only stores the hardware clock. It does not synchronize with internet time servers.

How Windows Time Synchronization Works

After Windows starts and the device has network connectivity, it synchronizes the system clock using Network Time Protocol (NTP). Bad Timestamp Error

Key Information:

If the device cannot communicate with the domain controller or NTP server, the system time may become inaccurate.Login Timestamp Error Domain Login Error

Additional Troubleshooting

If the issue still exists, try the following:

• ✅ Connect the laptop to the company VPN.
• ✅ Restart the computer.
• ✅ Ensure Windows Time service is running.
• ✅ Verify the correct Time Zone.
• ✅ Check if the CMOS battery is weak (time resets after every shutdown).
• ✅ Run Windows Update.
• ✅ Contact your IT administrator if the device belongs to a corporate domain.

Frequently Asked Questions (FAQ)

What causes Login Timestamp Error (40105)?
The most common cause is an incorrect system date and time.

Can a VPN connection fix this issue?
Yes. Once connected to the corporate VPN, Windows may synchronize the system time with the company's domain controller.

Does changing BIOS time permanently fix the issue?
It fixes the hardware clock, but Windows still synchronizes time using the Windows Time service after startup.

Which protocol is used for Windows time synchronization?
Windows uses Network Time Protocol (NTP) over UDP Port 123.

Can a dead CMOS battery cause this error?
Yes. If the CMOS battery is weak, the BIOS clock may reset after every shutdown, causing repeated timestamp errors.

Conclusion

The Login Timestamp Error (40105) is usually caused by an incorrect system clock rather than a problem with your user account.

In most cases, restarting the Windows Time service or correcting the BIOS date and time resolves the issue. Once the laptop synchronizes with the company's authentication server, users should be able to sign in successfully.

If the problem continues, connect the laptop to the corporate VPN or contact your organization's IT support team for further assistance.

Related Articles

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• Windows Time Service Not Running – Complete Fix Guide
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• How to Join a Windows Computer to a Domain
• How to Fix Windows Time Synchronization Failed