Migrate Sharepoint User Account to a New Login Name

There might be many occasions where we have to change the Users' account, could be the domain change or name change.

 Also another scenario is, if we have enabled Farm based authentication sharepoint adds some special characters to the account in the start like 'i:0#.w|' and if  we disabled it at later point, these names will not be changed.  We need to migrate / change the account names manually before people start using it. If not, we see 2 accounts for individual users.

we can achieve this functionality using Poweshell script. Considering above scenario, below is the script used to migrate resources in bulk when we are moving back form Farm based to windows authentication.

Below script is to get all the people present in the current system to a CSV File.

 function GetSPWebUsers($SiteCollectionURL)   
 {   
   [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint") > $null   
   $site = new-object Microsoft.SharePoint.SPSite($SiteCollectionURL)   
   $web = $site.openweb()   
   $siteUsers = $web.SiteUsers   
 @(foreach ($user in $siteUsers) {  
   $usergroup = New-Object System.Object  
      $usergroup | Add-Member -type NoteProperty -name AccountName -value $user.LoginName  
    Write-Output $usergroup   
 }) | Export-Csv c:\userlist.csv -NoTypeInformation   
   $web.Dispose()   
   $site.Dispose()   
 }   
 GetSPWebUsers $args[0]  
 #to execute, run the command as below  
 #GetSPWebUsers "http://<<site collection URL>>"  

By running above script, we get all the users' login names to a CSV file which will be used as an input of below code where we migrate individual users to the windows accounts which are formed by removing the starting set of special characters "i:0#.w|"

 Add-PSSnapin Microsoft.SharePoint.PowerShell  
 function MigrateUserOrGroups($csvFile)  
 {  
   #Getting the SPFarm object  
   $farm = Get-SPFarm  
   Import-Csv $csvFile | ForEach-Object{  
   Write-Host "Migrating User" $_.login "to" $_.login.Substring(7) -ForegroundColor Green  
   $farm.MigrateUserAccount( $_.login, $_.login.Substring(7), $false )  
   Write-Host "Migration Completed" -ForegroundColor Cyan  
   }  
   # $farm.Name  
 }  
 MigrateUserOrGroups $args[0]  
 #to execute, run the command as below  
 #MigrateUserOrGroups "c:\userlist.csv"  

You can modify the code as per your requirement.