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Windows Event Viewer displaying time synchronization events on a server monitoring dashboard
Event ID 33InformationSystemWindows

Windows Event ID 33 – System: Time Service Provider Time Synchronization

Event ID 33 indicates Windows Time Service has successfully synchronized system time with an external time source or encountered synchronization issues during the process.

Emanuel DE ALMEIDAEmanuel DE ALMEIDA
18 March 20269 min read 0
Event ID 33System 5 methods 9 min
Event Reference

What This Event Means

Windows Event ID 33 is generated by the Windows Time Service (W32Time) during time synchronization operations. This service maintains accurate system time by communicating with Network Time Protocol (NTP) servers or other time sources configured in your environment. The event provides detailed information about synchronization attempts, including success status, time corrections applied, and any errors encountered during the process.

The Windows Time Service operates as a hierarchical system where domain controllers typically serve as time sources for domain members, while standalone machines rely on external NTP servers. Event ID 33 captures the results of these synchronization attempts, logging both successful operations and failures that require administrative attention.

In Windows Server environments, accurate time synchronization is essential for Active Directory replication, distributed file system operations, and certificate-based authentication. Time discrepancies exceeding five minutes can cause Kerberos authentication failures, preventing users from accessing domain resources. Event ID 33 serves as an early warning system for time-related issues that could impact business operations.

The event details include the time source used, synchronization method, and any corrections applied to the local system clock. This information helps administrators troubleshoot time synchronization problems and verify that systems maintain acceptable time accuracy across the network infrastructure.

Applies to

Windows 10Windows 11Windows Server 2019/2022/2025
Analysis

Possible Causes

  • Successful time synchronization with configured NTP servers or domain controllers
  • Network connectivity issues preventing access to time sources
  • Firewall blocking NTP traffic on UDP port 123
  • Incorrect time source configuration in registry or Group Policy
  • Time source server unavailable or experiencing high latency
  • Virtual machine time synchronization conflicts with host systems
  • Hardware clock drift requiring frequent corrections
  • DNS resolution failures for configured time server hostnames
  • Authentication failures when accessing secure time sources
  • Time zone configuration changes affecting synchronization calculations
Resolution Methods

Troubleshooting Steps

01

Check Time Service Status and Configuration

Start by verifying the Windows Time Service is running and properly configured:

Get-Service W32Time | Select-Object Name, Status, StartType
w32tm /query /status
w32tm /query /configuration

Navigate to Event Viewer → Windows Logs → System and filter for Event ID 33 to examine recent synchronization attempts:

Get-WinEvent -FilterHashtable @{LogName='System'; Id=33} -MaxEvents 20 | Format-Table TimeCreated, LevelDisplayName, Message -Wrap

Check the current time synchronization status and identify any immediate issues:

w32tm /query /peers
w32tm /query /source
Pro tip: Use w32tm /monitor to test connectivity to all configured time sources and measure response times.
02

Test Network Connectivity to Time Sources

Verify network connectivity to configured time servers using PowerShell:

Test-NetConnection time.windows.com -Port 123 -InformationLevel Detailed
Test-NetConnection pool.ntp.org -Port 123

Check DNS resolution for time server hostnames:

Resolve-DnsName time.windows.com
nslookup pool.ntp.org

Test NTP communication directly using w32tm:

w32tm /stripchart /computer:time.windows.com /samples:5
w32tm /stripchart /computer:pool.ntp.org /samples:5

For domain environments, test connectivity to domain controller time sources:

w32tm /stripchart /computer:$env:LOGONSERVER.Replace('\\','') /samples:3
Warning: Firewall rules blocking UDP port 123 will prevent NTP synchronization. Check Windows Firewall and network firewall configurations.
03

Reconfigure Time Service Settings

Reset Windows Time Service configuration to defaults and reconfigure:

Stop-Service W32Time
w32tm /unregister
w32tm /register
Start-Service W32Time

Configure reliable NTP servers for workgroup computers:

w32tm /config /manualpeerlist:"time.windows.com,0x1 pool.ntp.org,0x1" /syncfromflags:manual /reliable:yes /update

For domain controllers, configure as authoritative time source:

w32tm /config /manualpeerlist:"time.nist.gov,0x1" /syncfromflags:manual /reliable:yes /update
Restart-Service W32Time

Verify the new configuration and force immediate synchronization:

w32tm /query /configuration
w32tm /resync /force

Check registry settings for time service configuration:

Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Parameters" | Select-Object NtpServer, Type
04

Investigate Virtual Machine Time Synchronization

For virtual machines, check hypervisor time synchronization settings. In Hyper-V environments:

Get-VMIntegrationService -VMName "YourVMName" | Where-Object Name -like "*Time*"

Disable VM time synchronization if using Windows Time Service:

Disable-VMIntegrationService -VMName "YourVMName" -Name "Time Synchronization"

For VMware environments, check VMware Tools time synchronization:

vmware-toolbox-cmd timesync status
vmware-toolbox-cmd timesync disable

Verify time synchronization is handled by Windows Time Service only:

w32tm /query /status
Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Config" | Select-Object AnnounceFlags
Pro tip: Avoid running both hypervisor time sync and Windows Time Service simultaneously as they can conflict and cause time drift.
05

Advanced Time Service Troubleshooting and Logging

Enable detailed W32Time logging for comprehensive troubleshooting:

w32tm /debug /enable /file:C:\temp\w32time.log /size:10000000 /entries:0-300

Configure registry settings for enhanced logging:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Config" -Name "EventLogFlags" -Value 3
Restart-Service W32Time

Monitor time synchronization in real-time:

Get-WinEvent -FilterHashtable @{LogName='System'; Id=33,35,36,37} -MaxEvents 50 | Sort-Object TimeCreated -Descending

Analyze time service performance and accuracy:

w32tm /query /status /verbose
w32tm /query /peers /verbose

Check for Group Policy settings affecting time synchronization:

Get-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\W32Time\*" -ErrorAction SilentlyContinue

Disable debug logging after troubleshooting:

w32tm /debug /disable
Warning: Debug logging generates large files quickly. Monitor disk space and disable logging after collecting necessary data.

Overview

Event ID 33 fires when the Windows Time Service (W32Time) performs time synchronization operations with configured time sources. This event appears in the System log whenever your Windows machine attempts to synchronize its clock with external NTP servers or domain controllers. The event typically indicates successful time synchronization but can also signal synchronization failures or configuration issues.

Windows Time Service is critical for domain authentication, certificate validation, and distributed system coordination. Event ID 33 provides visibility into time synchronization health, which directly impacts Kerberos authentication, file replication, and database transactions. Domain-joined machines synchronize with domain controllers, while workgroup computers use external NTP servers like time.windows.com.

This event becomes particularly important in virtualized environments where time drift is common, or in networks with strict time accuracy requirements for compliance or financial systems. Monitoring Event ID 33 helps administrators identify time synchronization problems before they cause authentication failures or application issues.

Frequently Asked Questions

What does Event ID 33 mean in Windows?+
Event ID 33 indicates that the Windows Time Service (W32Time) has performed a time synchronization operation. This event logs both successful synchronizations with NTP servers or domain controllers and any issues encountered during the synchronization process. The event provides details about time corrections applied, synchronization sources used, and the overall health of time synchronization on your system.
How often should Event ID 33 appear in my logs?+
Event ID 33 frequency depends on your time synchronization configuration. Domain-joined computers typically synchronize every 8 hours by default, while workgroup machines may sync more frequently. You should see this event regularly if time synchronization is working properly. Missing Event ID 33 entries for extended periods may indicate time service problems or network connectivity issues preventing synchronization.
Can Event ID 33 indicate time synchronization problems?+
Yes, Event ID 33 can indicate both successful synchronizations and problems. Check the event details and description for error messages or warnings. Common issues include network connectivity problems, firewall blocking NTP traffic, incorrect time source configuration, or conflicts between virtual machine time sync and Windows Time Service. The event message will provide specific details about any synchronization failures.
Why is accurate time synchronization important for Windows systems?+
Accurate time synchronization is critical for Windows domain authentication using Kerberos, which fails if time differences exceed 5 minutes between client and server. Time accuracy also affects certificate validation, file replication, database transactions, and compliance requirements. In virtualized environments, time drift can cause application issues and authentication failures across distributed systems.
How do I configure reliable time sources for Event ID 33?+
Configure reliable NTP servers using w32tm commands. For workgroup computers, use external NTP servers like time.windows.com or pool.ntp.org. Domain controllers should sync with authoritative sources like time.nist.gov. Use the command 'w32tm /config /manualpeerlist:"server1,0x1 server2,0x1" /syncfromflags:manual /reliable:yes /update' to configure multiple time sources for redundancy and restart the W32Time service after configuration changes.
Documentation

References (1)

1
Microsoft Learn - Windows Time ServiceComprehensive documentation for configuring and troubleshooting Windows Time Service across different Windows versions and deployment scenarios.https://learn.microsoft.com/en-us/windows-server/networking/windows-time-service/
Emanuel DE ALMEIDA
Written by

Emanuel DE ALMEIDA

Senior IT Journalist & Cloud Architect

Microsoft MCSA-certified Cloud Architect | Fortinet-focused. I modernize cloud, hybrid & on-prem infrastructure for reliability, security, performance and cost control - sharing field-tested ops & troubleshooting.

Tags
#event-id-33#time-synchronization#windows-time-service

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