Fiddler Ideas

I just had this problem. Google brought me here and I took the recommended approach of opening with 7Zip. It reveals two directories with unprintable names, one of which contains Fiddler4Setup.exe and Fiddler2Setup.exe. I extracted and ran Fiddler4Setup.exe and everything worked fine.

This is a 64-bit Windows 10 machine by the way.

This also just happened to me just now, on a Windows 7 machine - you try to launch fiddlersetup.exe and nothing happens.  Had to unzip it as described below then ran Fiddler4Setup.exe and that worked.

I even tried it with 7zip but application crashed at policies form

I had the same issue. Opening with 7ZIP and extracting the 4 installer worked. Turned out to be something with a group policy in my environment.

I had the same trouble (nothing happened when I clicked upon the .exe) opening the .exe in 7 zip then running the fiddlersetup.exe showed me the actual error which was "This program is blocked by group policy. For more information, contact your system administrator". I copied the Fiddlerv4Setup.exe from within the .exe (archive) into my local temp folder and ran it from there and it installed without any problems.

I had this same issue and was able to install by opening in 7ZIP

Is there any chance that you don't have write access to your TEMP folder? The combined installer does not handle this scenario correctly at present.

It's actually .NET2/.NET4 installer and you installed the .NET4 version. The folder name does not matter.

It does really seem like a bug in the joint installer, though, and it's one we have never seen so far. Are you still able to reproduce it? 

That seemed to work for me. I opened the exe with 7zip using Open Arcihve. I went into the folder with the 2.9 mb package size. There was a Fiddler2setup and a Fiddler4setup. I assumed the 2 meant 32 and 4 meant 64. i selected Fiddler4Setup.exe. It installed to a Fiddler2 folder (I assumed that the folder name was irrelevant.

This could be a bug in the new 32/64 joint installer. You might try opening the .EXE in 7ZIP, which will allow you to see the 32bit and 64bit standalone installers. Choose the correct one and run that.