I have a coworker who sends me fiddler logs from their session to help them diagnose the issue.  When I attempt to open the file I see the error in the attached image but when opening the file on coworker's computer there is no problem.  The user sends me the fiddler log via e-mail.  Any help would be appreciated.

Who changed fiddler's favicon to the ugly lime f! Please change to something more pleasing!

Can't seem to get it to capture any session data.  Also noticed that browsers, either IE64 or FireFox 27.0.1, lock up and won't display a page, until I kill Fillder and then they work again.  (I'm getting pages from localhost and elsewhere). 

I haven't tried Fiddler much, so don't have much experience with it.  Also I just downloaded the new version.  My win7 and browsers are up to date.

We are using FiddlerCore (v. 4.4.5.6) to capture traffic from our test suite that makes calls against the product servers (behind a VIP). And we are finding ghost requests hitting our servers - that is:
1. The Fiddler log from the client (saved using FiddlerCore) shows a single call.
2. The server logs from product servers shows that two different servers handled this same request.
The request has a unique  randomly generated secret token, so we know that it is the exact same request. So somehow a duplicate request is being fired that does not show up in the FiddlerCore trace. We discounted for now a potential issue with the F5-VIP for now.

This issue repros intermittently - so we can't really validate by just disabling FiddlerCore integration.

Is it possible for us to introduce such a scenario if we have a bug in how we integrate with the FiddlerCore session callbacks?

Or is there a possible bug in the version of FiddlerCore that we are using that might result in this behavior?

Appreciate any pointers,
Thanks!

After installing Fiddler, clicking on the Win8 Config tab at the top throws the following error:

Unitliy Not Installed
The EnableLoopback utility is not installed.
Visit http://fiddler2.com/r/?Win8EL to learn more?

I have downloaded the stand alone utility from the above mentioned URL and Fiddler still throws the same error message when the Win8 Config tab is clicked on

logo just bounces up and down on my dock

Dear Fiddler support,

I'm working with lighttpd 1.4.32 server on Linux, and JavaScript application on ExtJs widget.
There a problem in my application during file  uploading (about 30MB) to the server.
SOMETIMES, in IE, file is failed to be uploaded.
No errors in lighttpd, all parameters for file uploading are defined well. In other browsers, file is uploaded.
While debuging this problem, the following error is observed in console:
SEC7111: HTTPS security is compromised by res://ieframe.dll/dnserrordiagoff.htm
.....
All suggestions by Google didn't lead to proper result (update windows, decrease IE security options etc.)
BUT, when I'm using Fiddler application to catch response code, file is uploaded!!!
Please note, that other HTTP analyzers doesn't make such effect.

I'm inside this bug for several months. Quite frustrating.
I will be very appreciate if you could give me some direction why in Fiddler file is uploaded.
Thank you in advance, Marianna

Followed answer from http://stackoverflow.com/questions/11863037/fiddler-how-to-disable-overwrite-header-host

The Link is for "fiddler: how to disable overwrite Header Host"

Q: When using Fiddler, it pops up an alert dialog.

Fiddler has detected a protocol violation in session #14.

The Request's Host header did not match the URL's host component.

URL Host: proxy.music.pp.com Header Host: 119.147.22.41

And it shows that Fiddler changed HTTP Header's host to "proxy.music.pp.com", is there any way to diable Fiddler changing it?

A:
You can do this with rules.

Go into Customize rules, and find the function: OnBeforeRequest(oSession: Session)

Then add the following as the last line of that function:

if (oSession.HostnameIs("proxy.music.pp.com")) { oSession.host = "119.147.22.41"; }

I had this same issue with auto-updates from Avira Servers (Anti Virus).

As the above suggests I added     
if (oSession.HostnameIs("personal.avira-update.com")) {oSession.host = "184.51.102.18";}

In order to find the appropriate host address(es) use cmd.exe and enter nslookup personal.avira-update.com

Hello, I'm not sure whether this is a bug or something else, when Fiddler is capturing traffic and HTTPS decryption is on I cannot browse https://archive.org/

I get the error message "The connection to the server was reset while the page was loading." in Firefox. Same thing in Chrome, error code ERR_CONNECTION_RESET.

As soon as I turn off either HTTPS decryption or traffic capture in Fiddler I can browse the site again.

Any idea what might be the problem? I can browse other https websites fine, for instance https://www.httpsnow.org/ and https://google.com/

Hi,

I have a bit of conundrum. We have a webapp wich has built-in NTLM support. However this only works with Fiddler running in capture mode. If Fiddler is not running, the NTLM type 1 message that's supposed to be sent back to the server, by Internet Explorer, for some reason never gets sent.

To clarify, from http://davenport.sourceforge.net/ntlm.html#ntlmHttpAuthentication

=============================================================================================================
3. The client resubmits the request with an "Authorization" header containing a Type 1 message parameter.
=============================================================================================================

(3) never happens, unless fiddler is running in capture mode, then the ntlm handshake works like a charm.

Anyone knows what's going here?

cheers,Ritch