If Fiddlercore thrown an exception then it shut down. After that system proxy settings is switched on, but proxy not defined and i need go into browser settings and manually switch off 'use proxy server' setting. Is there a way to prevent that behavior and restore system proxy to 'no proxy' manually when fiddler fails? How can i do it?
There are a variety of strategies that you could undertake for this, but the proper fix is to not allow exceptions to bring down your process.
That means that you should be using try/catch blocks appropriately to handle exceptions rather than allowing them to kill your process.
If you're having problems with that, please share some code and I would be happy to help.