I was reading this link http://digital.withum.com/blog/pros-and-cons-of-sharepoint-modern-sites which mentioned the main differences between modern sites and classic sites, and it mentioned the following cons on modern pages :-

Modern sites are only created as site collections, which means you cannot use a site/sub-site structure. This is a debated topic as of late, but it’s important to remember that features like security inheritance through sub-sites doesn’t exist in the modern site framework.

but based on my test, when i create modern sites (modern team site OR modern communication site), i am able to create sub-sites under them as usual.. so i am not sure what the above cons is meant to be exactly ?

1 Answer 1


There's the "Modern UI" and the "Modern Site". While Microsoft does not stress the difference, the key difference is how users and security are handled. In the article you linked to they also said "features like security inheritance through sub-sites doesn’t exist in the modern site framework". Note that the "Modern Communications Site" does not use "Modern Site" features, just "Modern UI" pages.

If you create a "Modern Team Site", or any of the other "Modern Security" sites like those that are auto-created behind Outlook Groups, Teams, Planner, etc., you will find that you get these three things:

  • An Azure AD Office 365 Group.
  • An Exchange Email for the group.
  • A SharePoint Site Collection. (In Teams, Planner, etc this is behind the "Files" link.)

When in these backing SharePoint sites, you manage permissions to the top level site of these Site Collections by adding users to the "Owners" and "Members" Office 365 groups. When you create a subsite, you revert to managing access by using "classic" SharePoint permissions: 32 permissions rolled up into Permission Levels and managed by granting these Permission Levels to users or SharePoint Groups.

So, these subsites do not participate in "Modern Security", they do not get their own email address or their own Azure AD Office 365 Group and do not participate in other "Modern Site" features like hubs and discoverability. They are just Classic SharePoint sites with some Modern UI pages. It would not surprise me if the "Modern Sites" soon lost their options to create subsites.

  • Thanks for the reply. but i am not sure if I totally understand the case. now i created a new Modern Team site, and i got 3 groups (owner, member, visitor) which are also office 365 groups. then i created a new sub-site under this modern team site, and i chose to inherit the permission from the parent site, so on the subsite the 3 security groups where added to the sub-site and adding users to these 3 groups will be reflected inside the sub-site... so this means we can create subs-sites inside modern team site as usual.. Is this correct/valid, or i am missing something?
    – John John
    Commented Nov 20, 2018 at 11:02
  • can you advice on my above comments? thanks
    – John John
    Commented Nov 25, 2018 at 0:08
  • 1
    I'm assuming you are working with SharePoint Online. SharePoint on-prem does not support Modern Security/Office 365 Groups. If you are seeing Owner, Member and Visitor, then you are seeing the classic security SharePoint Groups. Modern Security uses Office 365 Groups, which only offer two roles: Owner and Member. Only the top level sites participate in Modern Security. While you can use the Classic groups, they do not get the full benefit of the Office 365 Group members. Commented Nov 26, 2018 at 3:25
  • 1
    Another way to describe this... A SharePoint Online Modern Team site gets: an Azure AD Office 365 Group, a SharePoint site collection and an Exchange email address. There is only one group, and users are assigned one of two roles in this group: Owner or Member. The three classic SharePoint Groups (sitename Owners, sitename Members and sitename Visitors) are created behind the scenes, but their use is discouraged. Users only get the full benefit of a Modern Team site if they are added to the Office 365 Group. Commented Nov 26, 2018 at 3:29
  • thanks for the reply. no it is clear, i think from now one it is preferred to follow the flat structure of sites instead of using sub-sites..
    – John John
    Commented Nov 26, 2018 at 13:29

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