Move/Promote Sub-Site to Site Collection in SharePoint Online

Question

We have numerous sub-sites that are under our top level site collection which we would like to move into their own site collection. Is this something that can be done via PowerShell? If so how? The solutions I have seen so far are for on-premise.

For example the sub-site https://foo.sharepoint.com/bar would become https://foo.sharepoint.com/sites/bar and show as a site collection in SharePoint Admin.

I am not sure what content is in these sub-sites and if they have unique permissions, do these need to be taken into consideration?

Answer 1

Workaround

There are no OOTB solutions for this since the SharePoint Online cmdlets are very limited, and Export-Import doesn't exist today.

However, you can save your subsite as template /_layouts/15/savetmpl.aspx and include content. When saved download the template from the solution gallery by clicking on the template name _catalogs/solutions/Forms/AllItems.aspx.

Create a new site collection in the SharePoint admin center, and in the custom tab select template later:

When the site collection is created, browse to the new site and hit the solution link. Upload the template and activate it. Go back to your root site url, and select your custom template.

Now you have "moved" your subsite to a site collection of its own, but without PowerShell.

On Premise or using Office Dev PnP PowerShell

First, create a Site Collection on url https://foo.sharepoint.com/sites/bar with the same template as your subsite https://foo.sharepoint.com/bar.

Second, use Export-SPWeb

Export-SPWeb https://foo.sharepoint.com/bar -Path "d:\temp\bar-export.cmp"

Third, use Import-SPWeb

Import-SPWeb https://foo.sharepoint.com/sites/bar -Path "d:\temp\bar-export.cmp" -Force

Now, verify that the imported web is equal to your subsite, before you delete the subsite.