peass-ng/PEASS-ng · error · System.Xml.XmlException

Invalid days of the week element.

Error message

Invalid days of the week element.

What it means

When reading a trigger definition from XML, an unknown/invalid element name inside the DaysOfWeek block cannot be parsed into the DaysOfTheWeek enum, and the library rethrows it as XmlException('Invalid days of the week element.'). The XML contains a day-of-week value outside the expected names (Monday..Sunday, AllDays, etc.).

Source

Thrown at winPEAS/winPEASexe/winPEAS/TaskScheduler/Trigger.cs:2637

            {
                switch (reader.LocalName)
                {
                    case "WeeksInterval":
                        WeeksInterval = (short)reader.ReadElementContentAsInt();
                        break;

                    case "DaysOfWeek":
                        reader.Read();
                        DaysOfWeek = 0;
                        while (reader.MoveToContent() == System.Xml.XmlNodeType.Element)
                        {
                            try
                            {
                                DaysOfWeek |= (DaysOfTheWeek)Enum.Parse(typeof(DaysOfTheWeek), reader.LocalName);
                            }
                            catch
                            {
                                throw new System.Xml.XmlException("Invalid days of the week element.");
                            }
                            reader.Read();
                        }
                        reader.ReadEndElement();
                        break;

                    default:
                        reader.Skip();
                        break;
                }
            }
            reader.ReadEndElement();
        }

        /// <summary>Writes the subclass XML for V1 streams.</summary>
        /// <param name="writer">The writer.</param>
        private void WriteMyXml(System.Xml.XmlWriter writer)
        {

View on GitHub (pinned to 53fb989abc)

Solutions

1. Fix the DaysOfWeek XML elements to use canonical English enum names (Monday, Tuesday, ...)
2. Validate the XML against the Task Scheduler schema before import
3. Wrap ReadXml in try-catch for XmlException and repair or reject the file

Example fix

// before
<DaysOfWeek><Mon/><Wed/></DaysOfWeek>
// after
<DaysOfWeek><Monday/><Wednesday/></DaysOfWeek>

static readonly string[] ValidDays = { "Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday" };
static bool DaysOfWeekXmlValid(XElement days) =>
    days?.Elements().All(e => ValidDays.Contains(e.Name.LocalName, StringComparer.Ordinal)) ?? true;

try { trigger.ReadXml(reader); }
catch (System.Xml.XmlException ex) when (ex.Message.Contains("days of the week")) { /* repair DaysOfWeek section or reject file */ }

When it happens

Trigger: Importing/reading task XML (ReadXml on a trigger) whose <DaysOfWeek> child element name is not a valid DaysOfTheWeek enum name — misspelled day, localized day names, or numeric values.

Common situations: Hand-edited or third-party-generated task XML with e.g. <Mon/> instead of <Monday/>, localized XML from non-English tooling, or corrupted export files.

Related errors

• Trigger.Repetition.Interval must be less than Trigger.Repeti
• Resources.Error_TriggerEndBeforeStart
• The current version of the native library (1.{osLibMinorVer}
• Task definition does not contain a version.
• Specified argument was out of the range of valid values. (Pa

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/67774381528e1b09. Report an issue: GitHub.