dotnet/wpf · error · IOException

SR.WriteFailure

Error message

SR.WriteFailure

What it means

CFStream.Write throws IOException with SR.WriteFailure when the underlying compound-file native IStream.Write reports a byte count different from the requested count. A partial write inside a compound file means the storage engine could not commit all bytes, so the stream surface treats it as a hard I/O failure rather than silently accepting a short write.

Solutions

1. Check available disk space and free space / quota before writing
2. Verify the compound file is not corrupt (try opening it with a repair tool) and the media is writable
3. Close and reopen the file, then retry the save operation
4. Copy content to a new file if the original container is damaged
5. Catch IOException around writes and implement save-to-temp-then-replace logic

Example fix

// before
cfStream.Write(data, 0, data.Length);
// after
try {
    cfStream.Write(data, 0, data.Length);
} catch (IOException ex) {
    throw new IOException("Compound file write failed (disk full or corrupt container?): " + ex.Message, ex);
}

// before writing
long free = new DriveInfo(Path.GetPathRoot(path)).AvailableFreeSpace;
if (free < data.Length + margin) throw new IOException("Insufficient disk space.");

try { cfStream.Write(buffer, 0, count); } catch (IOException ex) { /* check disk space / file corruption, retry to temp file */ }

When it happens

Trigger: Calling Write when the compound file is full, the disk is out of space, the file is locked/corrupted, or the native StgWrite fails partway and reports written != count.

Common situations: Disk-quota or free-space exhaustion while saving large documents; writes to a compound file on a flaky network share or removable media; corrupted OLE container files that fail mid-write.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• ArgumentOutOfRangeException(nameof(offset))
• can’t seek on baseStream
• File contains data in format version
• Image_CannotCreateTempFile
• No file exists at

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/d7a0784eb33ff0d3. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/WindowsBase/MS/Internal/IO/Packaging/CompoundFile/CFStream.cs:268

        PackagingUtilities.VerifyStreamWriteArgs(this, buffer, offset, count);

        int written = 0; // CLR guys have deemed this uninteresting?

        if ( 0 == offset ) // Zero offset is typical case
        {
            _safeIStream.Write( buffer, count, out written );
        }
        else // Non-zero offset
        {
            // Copy from indicated offset to zero-based temp buffer
            byte[] localBuffer = new byte[count];
            Array.Copy(buffer, offset, localBuffer, 0, count);
            _safeIStream.Write( localBuffer, count, out written );
        }

        if( count != written )
            throw new IOException(
                SR.WriteFailure);
}

    //------------------------------------------------------
    //
    //  Internal Methods
    //
    //------------------------------------------------------

    // Check whether this Stream object is still valid.  If not, thrown an
    //  ObjectDisposedException.
    internal void CheckDisposedStatus()
    {
        if( StreamDisposed )
            throw new ObjectDisposedException(null, SR.StreamObjectDisposed);
    }

    // Check whether this Stream object is still valid.

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