Not that long ago Microsoft started to roll out the option to disable custom scripts in your Office 365 Tenant. You can read up on it in the article Turn scripting capabilities on and off on the office.com site. While it is a great way to prevent users from adding custom scripts it disables some of the good stuff that was available for your administrators. However it is worth thinking of the options as it will disable sandboxed solutions, something you cannot ‘enforce’ otherwise.
From within the SharePoint Management screen you can find the settings in the settings tab.
An interesting note is that by default these settings are now rolled out as disabled. Thus preventing users from running custom script. All new tenants will have this option checked. With the option disabled a minor bug (or undocumented consequence) will occur. It turns out that you can no longer change the navigation mode of your site.
So imagine that you have a publishing site that uses the Structural Navigation and you decide to switch to Managed Navigation (or the other way around). Normally you would navigate to the Navigation Settings page, something you can still do, however when you try to save your changes you will end up with an access denied. The access denied page will only provide you with the following:
It turns out that the something on the page requires the scripting capabilities and that it can no longer be executed. So while custom script are disabled you will not be able to change the navigation settings, nor add new links or headings if you have the structural navigation selected. You can add new links to the quick launch if it is set to structural navigation by clicking the edit link. Any changes committed through that process are saved and visible for all your users.
Only changes that are set through the ‘navigation’ settings that are accessible through Site Settings – Navigation will fail once you click the OK to commit and save the changes. The only option currently available is to enable the custom scripts again. Within 24 hours you will be able to change the navigation as you would have expected.