Unexpected System Reboot Triggered by Software Management Policies After Daylight Saving Time Change

Products

• IT Management Suite

Issue/Introduction

In one environment, administrators observed that some systems restarted outside their expected maintenance window.

The Windows Event Log showed that the Altiris Agent (Symantec Management Agent) initiated an unexpected restart on March 9 2026 at 2:25 AM, even though the legitimate reboot had already occurred during the scheduled software update window on March 7 2026 at 6:30 PM.

Note: The dates and times are used as examples based on the original report of this issue.

 

Environment

ITMS 8.7.x, 8.8.x

Software Management / Managed Delivery Policies

Cause

Investigation of agent logs and policy execution history indicated that the reboot was triggered by a Managed Delivery Policy execution that incorrectly became “due” after the Daylight Saving Time (DST) clock change. 

Note: Software Management policies may also run outside their original schedule under certain conditions (for example if the Symantec Management Agent service was stopped or the scheduled execution was missed). This behavior is expected product behavior. In this case, however, the execution was related to the DST time adjustment.

 

Agent Log Timeline

Timestamp	Event
03/07/2026 18:30	Scheduled reboot executed successfully
03/08/2026 02:00	Daylight Saving Time change
03/09/2026 02:24:49	User logon detected
03/09/2026 02:24:59	Managed Delivery Policy executed
03/09/2026 02:25:18	Reboot triggered

Improvements have been implemented to ensure that when a timezone change is detected, the agent adjusts internal scheduling data for Managed Delivery Policies to prevent unintended re-execution.

Resolution

Additional investigation identified that the behavior is related to how the agent evaluates policy schedules when system timezone changes occur (such as during Daylight Saving Time transitions).

This issue has been targeted for a fix under ITMS 8.8.2 release. Improvements were introduced in the Software Management Framework (SMF) Agent to handle timezone changes more accurately. 

Current workaround for those pre-8.8.2 Release:

Avoid scheduling critical policies shortly "before" the Daylight Saving Time change window.

Policies scheduled "after" the DST change are not affected.

Additionally, if a policy must execute strictly at its scheduled time, configure the schedule to use the Exact execution modifier ("Computer is available at the exact scheduled time" checkbox) in the schedule advanced settings. This ensures the policy will only run at the exact scheduled time and will not execute later if the schedule is missed.

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Immediate Mitigation

If production systems have strict reboot windows, consider the following safeguards.

1. Review Managed Delivery Policy Schedules

On the SMP Console:

1. Navigate to
   
   Manage > Policies > Software > Managed Delivery

2. Locate the affected Managed Delivery Policy.

3. Review the Schedule section.

4. Verify:

   • No unexpected additional schedules exist.

   • Scrollbars in the schedule view do not hide additional triggers.

2. Review Reboot Tasks in the Policy

Check the reboot task configuration.

1. Navigate to:

Manage > Jobs and Tasks > System Jobs and Tasks

2. Locate the associated task.

3. Verify the conditions:

Setting	Expected Value
Trigger	Only after patch installation
Schedule	Controlled maintenance window
Run Conditions	Not triggered by policy reevaluation

3. Validate Agent Policy Data

On affected endpoints verify the policy scheduling metadata.

Check the directory:

<agentinstalldir>:\Program Files\Altiris\Altiris Agent\Agents\SoftwareManagement\data

 

Each policy has a file:

policy_GUID

These files contain persisted scheduling metadata including timezone information.

4. Collect Diagnostic Data

If the issue reoccurs, collect the following from the affected client machine.

Data	Location
Task execution history	C:\Program Files\Altiris\Altiris Agent\TaskManagement\TaskHistory
Software Management data	C:\Program Files\Altiris\Altiris Agent\Agents\SoftwareManagement\data
Software Delivery policy data	C:\Program Files\Altiris\Altiris Agent\Agents\SoftwareManagement\Software Delivery\AeXSWDPolicy.xml
Client policies	C:\Program Files\Altiris\Altiris Agent\Client Policies

Also export:

• Windows Event Logs

  • Application

  • System
    
    

5. Confirm Resolution

After the DST event and policy refresh cycles:

1. Verify policies only execute during scheduled windows.

2. Confirm no unexpected entries appear in Agent UI > Task Status tab > Task History

3. Check Event Viewer for unexpected reboot triggers.

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Additional Technical Details (Post-Fix Behavior in ITMS 8.8.2 Release)

When a timezone change is detected, the SMF Agent performs an internal adjustment of policy scheduling data.

The agent:

• Detects timezone (bias) changes during the main SMF thread execution
• Runs an adjustment routine for non-running Managed Delivery Policies
• Updates internal scheduling data using persisted policy history
• Rewrites policy data files with corrected time references

Relevant policy data is stored under:

C:\Program Files\Altiris\Altiris Agent\Agents\SoftwareManagement\data\<GUID>.xml

 

Example Agent Log Entries

The following log entries may be observed after the fix when a timezone change occurs:

Detected timezone change. About to adjust the policies' schedule check data

Adjusting timezone for Policy {GUID}

Schedule checks were adjusted for policy {GUID}

Adjusted X policies

Policy {GUID} is running. Will not adjust schedule check timezone

Schedule checks were adjusted for policy {GUID} ... EXAMPLE POLICY NAME