If you create a Team Site by default you can no longer change the masterpage from 'Site Settings' / 'Look and Feel'. You must first now enable the Site Collection feature:
"SharePoint Server Publishing Infrastructure"
and the Manage Site Feature:
"SharePoint Server Publishing"
To do this go to 'Site Settings' under 'Site Actions':
"SharePoint Server Publishing Infrastructure"
and the Manage Site Feature:
"SharePoint Server Publishing"
To do this go to 'Site Settings' under 'Site Actions':
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