Secure Lock Screen clock may appear up to 30 seconds behind

Issue

On the Windows Secure Lock screen (for example, after restart, during initial sign-in, or after pressing Ctrl + Alt + Delete), the displayed time may not immediately change when a new minute begins.

The clock display can appear delayed by up to 30 seconds after the actual minute change. If the device time is ahead, the display may refresh earlier than expected because updates follow a fixed 30-second OS interval.

Cause

This behavior is by design.

The Secure Lock screen runs on the Winlogon secure desktop under the SYSTEM account and refreshes the clock every 30 seconds. Because this polling interval is not aligned to minute boundaries, the displayed time can update up to 30 seconds after the actual minute change.

This behavior is specific to the Secure Lock screen (LogonUI).

By comparison, the user lock screen (LockApp) shown after pressing Windows key + L runs in the user session and uses a dynamic timer that refreshes at the next minute boundary. As a result, it typically updates almost immediately.

Both experiences use the same Windows kernel system clock. The difference is only in how often the time is refreshed on screen.

Impact

This is a visual-only issue affecting the Secure Lock screen clock display.

There is no impact to:

• System time accuracy

• W32Time or NTP synchronization

• Event logs, auditing, or timestamps

• Authentication or system security

• Compliance scenarios

All logging and security timestamps continue to come directly from the Windows kernel system clock.

Workaround

No workaround is required.

The displayed time updates automatically within the normal 30-second refresh interval.