Sitecore update file upload request filtering module error

When using Sitecore's update installation wizard to install a new version of Sitecore, I was getting the following error message when trying to upload the update file.

The request filtering module is configured to deny a request that exceeds the request content length.

Request filtering module error message

In the upgrade guide it mentioned the the maxAllowedContentLength setting needed to be updated in the web.config file. This is a setting which controls the maximum file size (in bytes) that can be uploaded to the web server.

Web.config maxAllowedContentLength

In my case, this had been updated (and IIS restarted) which should of allowed a maximum size of 4gb, where the update file was only 1gb. The error was still occurring.

It turns out that the instruction stated "\wwwroot\<instance name>\Website\sitecore\admin\web.config" where I had misread and edited "\wwwroot\<instance name>\Website\web.config".

I can't be the only silly person to make this mistake, hopefully this saves someone else some time :)