Simple Powershell script to bulk reset passwords from a text file containing one user per line. This makes use of the Get-ADUser, Set-ADUser, and Set-ADAccountPassword Powershell active directory cmdlets.

# import the AD module
if (-not (Get-Module ActiveDirectory)){
	Import-Module ActiveDirectory -ErrorAction Stop            

# set new default password
$password = ConvertTo-SecureString -AsPlainText "Password01" -Force  

# get list of account names (1 per line)
$list = Get-Content -Path c:\scripts\users.txt

# loop through the list
ForEach ($u in $list) {

	if ( -not (Get-ADUser -LDAPFilter "(sAMAccountName=$u)")) { 
		Write-Host "Can't find $u" 
	else { 
		$user = Get-ADUser -Identity $u
		$user | Set-ADAccountPassword -NewPassword $password -Reset
		$user | Set-AdUser -ChangePasswordAtLogon $true
		Write-Host "changed password for $u"