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Evtx.Document

Returns the events in a Windows XML Event Log file (.evtx) as a table.

Syntax​

Evtx.Document(
    source as binary,
    optional options as record
) as table

Remarks​

An .evtx file is not XML on disk. It is a chunked container of binary XML built on per-chunk template definitions with back-references and typed substitution values, which is why reading one normally means the Windows Event Log API, a SIEM, or a compiled parser. This function decodes the format directly, from a plain binary — so a log copied off an incident machine reads in Power BI with nothing installed, on any host.

One row per event, with the System fields already extracted into columns: RecordId, TimeCreated, Provider, EventId, Level, LevelName, Task, Opcode, Keywords, Channel, Computer, ProcessId, ThreadId, UserId, EventData (a record of the event's payload fields) and Xml (the rendered event XML).

Options:

  • IncludeXml : A logical (true/false). Emit the rendered XML of every event in the Xml column (default is true). Set false to skip rendering when only the extracted columns are needed — noticeably faster on large logs. Note that false removes the Xml column rather than nulling it, so a downstream step that references [Xml] breaks.
  • Encoding : A TextEncoding.Type or codepage number for AnsiString (type 0x02) values, default Windows-1252. Unicode strings are unaffected.
  • MaxRows : A number. Stop after this many events.
  • Strict : A logical (true/false). Default false, which is what makes a dirty log readable: records that fail to parse are skipped and counted in Evtx.SkippedRecords, and chunks with bad signatures are ignored. True makes any malformation an error.

Examples​

Example #1​

Read a log, skipping XML rendering for speed.

Evtx.Document(File.Contents("C:\logs\Security.evtx"), [IncludeXml = false])

Example #2​

Failed logons by account, from the raw log.

let
    Events = Evtx.Document(File.Contents("C:\logs\Security.evtx"), [IncludeXml = false]),
    Failed = Table.SelectRows(Events, each [EventId] = 4625),
    Named  = Table.AddColumn(Failed, "Account", each [EventData][TargetUserName]?)
in
    Table.Group(Named, {"Account"}, {{"Attempts", Table.RowCount, Int64.Type}})

Example #3​

Check whether anything was lost before trusting a count. A log recovered from a crashed machine can parse happily and still be missing records.

let
    Events = Evtx.Document(File.Contents("C:\logs\Security.evtx")),
    Meta   = Value.Metadata(Events)
in
    [ Dirty = Meta[Evtx.IsDirty], Skipped = Meta[Evtx.SkippedRecords] ]

Supported​

EVTX versions 3.1 and 3.2 (Windows Vista through current); binary XML templates, resident and back-referenced, and nested binary XML values; every documented substitution value type — strings, integers, floats, boolean, binary, GUID, FILETIME, SYSTEMTIME, SID, hex32/64, size_t, Unicode string arrays; dirty files, where chunks are found by signature scan rather than the header count and record recovery stops at the first corrupt record in a chunk; records outside any template (raw fragments).

Not supported​

  • Legacy .evt files — an entirely different format, clear error.
  • CRC32 checksum verification. Checksums are ignored; corruption surfaces as skipped records instead.
  • Carving records out of chunk slack space.

64-bit integer values beyond 253 lose precision. FILETIME timestamps decode exactly to the 100 ns tick.

Metadata​

Evtx.Version, Evtx.IsDirty, Evtx.IsFull, Evtx.NextRecordId, Evtx.ChunkCount, Evtx.DeclaredChunkCount, Evtx.SkippedRecords.

Category​

Driverless connectors