Can I force all the sub sites to be using the same master page

Question

I have created a sub site and I define a custom master page for it. Then I save it as a template. After that I started creating sub sites based on the template, where all the subsites get the custom master page as defined in the template.

Now let say I have 20 sub sites , and I want to do a change to all the sub sites master pages such as changing the footer or the search box location. Currently each of the 20 sub site have a separate master page and to apply such a change I will need to modify the related 20 master pages separately. Now since I will always need the same master page to be used inside all the subsites including any future changes , so is there a way in SP to force the sub sites to be using the same master page (shared master page) , so if I modify the shared master page it will affect all the sub sites at once ? Thanks

Answer 1

You can open top level site then

Site Settings -> Master Page -> Check Reset all subsites to inherit this site master page setting and click Ok

This will set top level master page to all Sub Sites.

Answer 2

You can try the below script to change the masterpage for all subsites.

$site = Get-SPSite http://portal/sites/collaboration
$site | Get-SPWeb -limit all | ForEach-Object { $_.MasterUrl = "/sites/collaboration/_catalogs/masterpage/custom.master";$_.Update() }
$site.Dispose()

Changing the master page on SharePoint sites with PowerShell

Also check this one: Powershell so all of subsites/sub-sub sites inherit from Parent site's master page