Unable to add 'Global.asax' to the Web site. An unknown WinINet error has occurred (code 12113).

Posted on Thursday, January 1, 2015 at 12:00 AM into csharp & code by Steve Woods.
Roughly a 1 minute read.

When publishing - especially via FTP (people still use that?) - using Visual Studio, you may come across the error:

Connecting to ftp://xxx.xxx.xxx.xxx Unable to add 'Global.asax' to the Web site. An unknown WinINet error has occurred (code 12113).

To solve it, you must simply add Visual Studio to your firewall exclusion list - the error is a result of the firewall blocking Visual Studio from accessing your FTP server.