peass-ng/PEASS-ng · warning · NotSupportedPriorToException

NotSupportedPriorToException

Error message

NotSupportedPriorToException

What it means

NotSupportedPriorToException signals that a property introduced in Task Scheduler 2.1 (Windows 7/Server 2008 R2) is being used on a task running on an older engine. UseUnifiedSchedulingEngine requires v2Settings2 (V2.1) or v2Settings3 (V2.2); when neither interface is available the setter throws with TaskCompatibility.V2_1. The library enforces minimum OS/compatibility versions per property.

Source

Thrown at winPEAS/winPEASexe/winPEAS/TaskScheduler/Task.cs:3487

        [XmlIgnore]
        public bool UseUnifiedSchedulingEngine
        {
            get
            {
                if (v2Settings2 != null)
                    return v2Settings2.UseUnifiedSchedulingEngine;
                if (v2Settings3 != null)
                    return v2Settings3.UseUnifiedSchedulingEngine;
                return false;
            }
            set
            {
                if (v2Settings2 != null)
                    v2Settings2.UseUnifiedSchedulingEngine = value;
                else if (v2Settings3 != null)
                    v2Settings3.UseUnifiedSchedulingEngine = value;
                else
                    throw new NotSupportedPriorToException(TaskCompatibility.V2_1);
                OnNotifyPropertyChanged();
            }
        }

        /// <summary>Gets or sets a boolean value that indicates whether the task is automatically disabled every time Windows starts.</summary>
        /// <exception cref="NotSupportedPriorToException">Property set for a task on a Task Scheduler version prior to 2.2.</exception>
        [DefaultValue(false)]
        [XmlIgnore]
        public bool Volatile
        {
            get => v2Settings3 != null && v2Settings3.Volatile;
            set
            {
                if (v2Settings3 != null)
                    v2Settings3.Volatile = value;
                else
                    throw new NotSupportedPriorToException(TaskCompatibility.V2_2);
                OnNotifyPropertyChanged();

View on GitHub (pinned to 53fb989abc)

Solutions

1. Verify the target machine/TaskScheduler supports V2_1 (Windows 7 / Server 2008 R2 or newer) before setting the property
2. Set the TaskDefinition's Compatibility to TaskCompatibility.V2_1 or higher so the V2.1 settings interface is created
3. Guard the assignment with a version/compatibility check and skip the property on older systems
4. Catch NotSupportedPriorToException and degrade gracefully if the setting is optional

Example fix

// before
task.Definition.Settings.UseUnifiedSchedulingEngine = true;
// after
if (task.Definition.Settings.Compatibility >= TaskCompatibility.V2_1)
    task.Definition.Settings.UseUnifiedSchedulingEngine = true;
else
    Log("UseUnifiedSchedulingEngine requires Task Scheduler 2.1+");

if (def.Settings.Compatibility < TaskCompatibility.V2_1) { Log("Requires TS 2.1"); return; }
def.Settings.UseUnifiedSchedulingEngine = true;

bool SupportsV2_1(TaskDefinition def) => def != null && def.Settings.Compatibility >= TaskCompatibility.V2_1;

try { def.Settings.UseUnifiedSchedulingEngine = v; } catch (NotSupportedPriorToException) { Log("Requires Win7+/TS 2.1"); }

When it happens

Trigger: Setting Task.Settings.UseUnifiedSchedulingEngine on a task whose underlying settings object is only V2.0 or V1 — i.e. running on Windows Vista/Server 2008 or earlier, or on a task definition whose Compatibility is below V2_1.

Common situations: Managing scheduled tasks remotely on pre-Win7 machines; a codebase written for Win7+ deployed to Server 2008; copying a task definition that uses the unified scheduling engine to an older host.

Related errors

• A maximum of 32 actions is allowed within a single task.
• Attachments array cannot contain more than 8 items.
• Each value of the array must contain a valid file reference.
• Under Windows 8 and later, EmailAction objects are converted
• Index is not a valid index in the ActionCollection

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/ee2b1908166ae41d. Report an issue: GitHub.