Deleting Orphan Features
Many of the times in deployment you many face issue of orphan features due to deployment fails, in that case features remains orphan and while redeployment it complains that feature is already installed.
In those cases you need to remove those orphan entries. you can use below command to get all orphan features
Get-SPFeature | ? { !$_.Scope }
And to delete all those orphan features you can use
Get-SPFeature | ? { !$_.Scope } | % { $_.Delete() }
Deleting Orphan Sites
Same way you might end up sometimes in orphan sites and that you can remove by using below command.
$site = Get-SPSite “your site collection name”;
$siteId = $site.Id;
$siteDatabase = $site.ContentDatabase;
$siteDatabase.ForceDeleteSite($siteId, $false, $false);
For more information on orphan sites you may refer http://social.technet.microsoft.com/wiki/contents/articles/21968.sharepoint-deleting-orphan-sites.aspx
Happy Reading! 🙂