Hi Shaun,

Our internal investigation of the issue showed that the problem is caused by an update in Fiddler Classic and Fiddler Everywhere. We've changed the ZIP library in our UI products to improve the performance and the ability to load more sessions at any moment, but that came with a change where both applications are now only reading SAZ files generated with UNIX-style paths. The above change means that we need to change the FiddlerCore utilities so that any automatically generated tracks should always use UNIX paths, not Windows ones.

We've logged this task up for implementation in a future release of FiddlerCore, but until then, please use a custom implementation where you explicitly pass the file name with UNIX-style paths.

Regards,
Nick Iliev
Progress Telerik

Hello Shaun Becker,

Based on the provided information and the case description (especially 1st and 3rd points -  identical content while comparing both files), it seems that issue is related to how the SAZ files are saved through the custom SAZ writer. The Fiddler products (including Fiddler Classic and Fiddler Everywhere) are reading SAZ files that are using UNIX-style paths with a forward slash (for example, "raw/1_c.txt"). The custom SAZ writer probably uses Windows-style paths with a backslash (for example, "raw\1_c.txt"). That different path style will also explain why the repaired and the original files output the same content but are causing different behavior. I hope the above help you in solving the issue.

As a side note, you could test the WriteSessionArchive with the basic example below that utilizes the built-in options to create a directory.

private static void SaveSessionsToDesktop(IEnumerable<Session> sessions, string password)
{
    string filename = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) +
                                Path.DirectorySeparatorChar + DateTime.Now.ToString("hh-mm-ss") + ".saz";

    string response;
    try
    {
        if (sessions.Any())
        {
            bool success = Utilities.WriteSessionArchive(filename, sessions.ToArray(), password, false);
            response = $"{(success ? "Wrote" : "Failed to save")}: {filename}";
        }
        else
        {
            response = "No sessions have been captured.";
        }
    }
    catch (Exception ex)
    {
        response = $"Save failed: {ex.Message}";
    }
}

Regards,
Nick Iliev
Progress Telerik