Do you have a question about WordPress or BoldGrid? You’ve come to the right place. Feel free to post your questions or browse other visitors questions and comments as well.
Sorry for any problems with Customization of your site after updating to WordPress 4.9.1. We would need more information on the issue as BoldGrid is working in version 4.9.1 as far as we can tell. Make sure that your plugins are updated to the latest version and turn off or reset caching if you are using it. If you continue to have the problem, then please provide us a URL and more information concerning the problem that you are having.
Sorry for the problem with the Customize option after upgrading to WordPress 4.9.1. As per my last answer on the issue, we would need more information concerning the versions of the BoldGrid plugin you’re using. There was an update to the plugin, so be sure to make sure that it is updated as it may resolve your problem.
We spent quite some time testing this with the Cobalt theme, and are not experiencing any issues. I recommend Displaying and Logging PHP Errors, Warnings, and Notices on your site. This may provide a more specific error message. Also try disabling any 3rd party plugins, except for BoldGrid. This will rule out if the issue is being caused by a plugin conflict.