Exchange Online PowerShell script to remove added permissions on all foldders of an user's mailbox. Can be used with Exchange Online PowerShell module with MFA.

EOL-RemoveAllMailboxFolderPermissions.ps1

<#
.SYNOPSIS
EOL-RemoveAllMailboxFolderPermissions.ps1

.DESCRIPTION 
A script to remove permissions from all folders present in a particular user mailbox.

.OUTPUTS
Console output for progress.

.PARAMETER Mailbox
The mailbox that the folder permissions will be removed from. Format: [email protected] (UserPrincipalName or Primary SMTP address).

.EXAMPLE
.\EOL-RemoveAllMailboxFolderPermissions.ps1 -Mailbox [email protected]

This will remove all users permissions on al folders of John Doe mailbox.

.NOTES
Original script by: Paul Cunningham
Original source: https://github.com/cunninghamp/Powershell-Exchange/tree/master/MailboxFolderPermissions

#>


[CmdletBinding()]
param (

	[Parameter( Mandatory=$true)]
	[string]$Mailbox

)


$exclusions = @("/Sync Issues",
                "/Sync Issues/Conflicts",
                "/Sync Issues/Local Failures",
                "/Sync Issues/Server Failures",
                "/Recoverable Items",
                "/Deletions",
                "/Purges",
                "/Versions",
                "/PersonMetadata",
                "/Quick Step Settings",
                "/Suggested Contacts",
                "/Yammer",
                "/Yammer Root",
                "/Yammer Root/Feeds",
                "/Yammer Root/Inbound",
                "/Yammer Root/Outbound",
                "/Calendar Logging"
                )



$mailboxfolders = Get-MailboxFolderStatistics $Mailbox | Where {!($exclusions -icontains $_.FolderPath)} | Select FolderPath

foreach ($mailboxfolder in $mailboxfolders)
{
    $folder = $mailboxfolder.FolderPath.Replace("/","\")
    if ($folder -match "Top of Information Store")
    {
       $folder = $folder.Replace(“\Top of Information Store”,”\”)
    }
    
    $identity = "$($mailbox):$folder"

    Write-Host "Getting permissions on $identity" -ForegroundColor Gray

    $folderPermission = Get-MailboxFolderPermission -Identity $identity | Where-Object {$_.User -notmatch "Default" -and $_.User -notmatch "Anonymous"}

    if ($folderPermission)
    {
        try
        {
            $folderPermission | ForEach-Object {

                    Remove-MailboxFolderPermission -Identity $identity -User $_.User.ADRecipient.UserPrincipalName -Confirm:$false -ErrorAction STOP
                    Write-Host "Removed permissions of $($_.User) on $($identity)" -ForegroundColor Green
                
                 }

        }
        catch
        {
            
            Write-Warning $_.Exception.Message
        
        }
    }
}