Fiddler is installed and run as a service  in "user1" account, ​Now how do I make web traffic flow through Fiddler when logged in from a different account?

 

Thank you.

To capture Fiddler from any user account, simply set that user account's proxy settings to 127.0.0.1 on port 8888 using Internet Explorer's Tools > Internet Options > Connections > LAN Settings screen.

Regards,
Eric Lawrence
Telerik

I have set ​the proxy settings to 127.0.0.1 on port 8888, but chrome gives me this message

net::ERR_CERT_INVALID

any solution?

You haven't mentioned which operating system you're using. To get other user-accounts to trust the Fiddler root certificate, it must be installed in the machine certificate store, not the user store. By default, Fiddler will prompt you to do this on Windows 8 and later. 

From the Fiddler book:

1.        In Fiddler’s Tools > Fiddler Options > HTTPS tab, click Export Root Certificate to Desktop.

2.        Launch mmc.exe.

3.        Click File > Add/Remove Snap-In.

4.        Select the Certificates snap-in and press Add.

5.        When prompted This snap-in will always manage certificates for: choose Computer Account

6.        Click Local Computer, then Finish, then OK.

7.        Open the Certificates (Local Computer) node.

8.        Right-click the Trusted Root Certificate Authorities folder and choose All Tasks > Import.

9.        Choose the file you exported in step #1 and import it.

Regards,
Eric Lawrence
Telerik