I've had the same behaviour with the following config for Forge 1.11.2:
The error message is:
{{Failed to download file, the file contents differ from what was }}{{ expected. Name: jopt-simple-4.6.jar URL: }}{{ https://libraries.minecraft.net/net/sf/jopt-simple/jopt-simple/4.6/jopt-simple-4.6.jar}}{{ Filename on disk: jopt-simple-4.6.jar Path: }}{{ C:\Users\MY_USER_NAME\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.6\jopt-simple-4.6.jar}}{{ Exists: File}}
This is resolved by either:
a) downloading jopt-simple-4.6.jar from the URL supplied, and placing in the path listed; or
b) installing vanilla 1.11.2 first, launching it, and then trying forge1.11.2-13.20.0.228 again.
Kirsty McNaught
I've had the same behaviour with the following config for Forge 1.11.2:
The error message is:
{{Failed to download file, the file contents differ from what was }}
{{ expected. Name: jopt-simple-4.6.jar URL: }}
{{ https://libraries.minecraft.net/net/sf/jopt-simple/jopt-simple/4.6/jopt-simple-4.6.jar}}
{{ Filename on disk: jopt-simple-4.6.jar Path: }}
{{ C:\Users\MY_USER_NAME\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.6\jopt-simple-4.6.jar}}
{{ Exists: File}}
This is resolved by either:
a) downloading jopt-simple-4.6.jar from the URL supplied, and placing in the path listed; or
b) installing vanilla 1.11.2 first, launching it, and then trying forge1.11.2-13.20.0.228 again.