Some responses cannot be decrypted.
Sample HAR file: https://mega.nz/#!pBUhCAxb!HF7wahVT1RJog9dHNc3NQji5nZ3BNrVFzrkWJ1GI1S0
for example, search for: lrR/zv7/RNCaLj/9XY472V/Z1yMyt/KYbZU/Og8JiI/
It is readable in Chrome dev tools
the same request in https://toolbox.googleapps.com/apps/har_analyzer/
Ok, thanks.
The problem here is that HAR file captured drops a critical HTTP response header:
{
"name": "Content-Encoding",
"value": "gzip"
},
If you add this header back to the response (e.g. use F2 to enable editing, then use the Headers inspector to add it), then the response can be properly decompressed by Fiddler. If you reissue the request to the original server (just select the request line in Fiddler and tap R) you will see that the server includes the necessary header.
You should file a bug against the tool that generated this HAR file.