Cannot Upload a Favicon
Sometimes a Favicon was successfully uploaded, but still not showing on the site. In this case, clear the website cache and refresh your site. Occasionally it may take several hours to be applied.
If you’re getting an error when uploading the .ico file to WordPress, or the following error message when trying to upload a file, this is most probably caused by restrictions from WordPress:
The easiest way to fix this is to use the Disable Real MIME Check plugin. Once installed and activated, you should be able to upload all files that were allowed before 4.7.1.
It has been reported that this issue will be fixed in the 4.7.3 WordPress version, but until then this plugin is a workaround for disabling the recently introduced restrictions.
Don’t forget to remove the plugin once WordPress 4.7.3 is available!