SharePoint Online: Remove User or Group from Folder Permissions using PowerShell

Requirement: Remove user from folder permissions in SharePoint Online.

How to Remove user from folder permissions in SharePoint Online?
How to restrict access to folder in SharePoint Online? To remove a user or group from SharePoint Online Folder's permissions, follow these steps:

Navigate to your SharePoint Online list or library where the target folder is located.
Click on "Details" from the specific Folder's context menu >> In the Details pane, Click on "Manage Access" and then "Advanced" links. This takes you to the "Advanced Permissions" page
From the ribbon, Click on "Stop Inhering Permissions" button and confirm the prompt.
Now, You'll get the list of users and groups who have permissions on the folder. When you break the permission, SharePoint copies permissions from its parent (List/library in our case!) .
Select the users and groups you want to remove permission from folder and confirm the prompt.
That's all. We've removed user from folder permissions.

Remove User from folder permissions using PowerShell:
Here is my PowerShell to remove user permission from folder in SharePoint Online.

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

Function Remove-SPOUserPermissionsFromList()
{
  param
    (
        [Parameter(Mandatory=$true)] [string] $SiteURL,
        [Parameter(Mandatory=$true)] [string] $FolderURL,
        [Parameter(Mandatory=$true)] [string] $UserAccount
    )
 
    Try {
        #Get credentials to connect
        $Cred= Get-Credential
        $Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)
 
        #Setup the context
        $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
        $Ctx.Credentials = $Credentials
        $Web = $Ctx.web
 
        #Get the Folder
        $Folder = $Web.GetFolderByServerRelativeUrl($FolderURL)
        $Ctx.Load($Folder)
        $Ctx.ExecuteQuery()
     
        #Break Permission inheritence - Keep all existing list permissions & Don't keep Item level permissions
        $Folder.ListItemAllFields.BreakRoleInheritance($True,$False)
        $Ctx.ExecuteQuery()
        Write-host -f Yellow "Folder's Permission inheritance broken..."
      
        #Get the SharePoint User object from the site
        $User = $Web.EnsureUser($UserAccount)
        $Ctx.load($User)

        #Get permissions assigned to the folder
        $Ctx.Load($Folder.ListItemAllFields.RoleAssignments)
        $Ctx.ExecuteQuery()

        #Check if the user has permission on the list
        [Bool]$UserFound = $False
        ForEach($RoleAssignment in $Folder.ListItemAllFields.RoleAssignments)
        {
            $ctx.Load($RoleAssignment.Member)
            $Ctx.ExecuteQuery()

            #remove user permission from folder
            If($RoleAssignment.Member.LoginName -eq $User.LoginName)
            {
                $Folder.ListItemAllFields.RoleAssignments.GetByPrincipal($User).DeleteObject()
                $Ctx.ExecuteQuery()
                $UserFound = $True
                Write-host "User Permissions Removed from the List Successfully!" -ForegroundColor Green  
            }
        }
        #If user doesn't exist in list permissions
        If($UserFound -eq $False) { Write-host "User Not found in List Permissions!" -ForegroundColor Red}
    }
    Catch {
       write-host -f Red "Error Removing permissions from the Folder!" $_.Exception.Message
    }
}

#Config Variables
$SiteURL="https://crescent.sharepoint.com"
$FolderURL="/Project Docs/Active"
$UserAccount="Salaudeen@Crescent.com"

#Call the function to remove user permissions from a list
Remove-SPOUserPermissionsFromList -SiteURL $SiteURL -FolderURL $FolderURL -UserAccount $UserAccount

This PowerShell removes user from folder permissions on given parameters.

Remove Group from Folder Permissions using PowerShell
Similarly, to remove a SharePoint group from folder's permissions, use this PowerShell script.

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

Function Remove-SPOGroupPermissionsFromList()
{
  param
    (
        [Parameter(Mandatory=$true)] [string] $SiteURL,
        [Parameter(Mandatory=$true)] [string] $FolderURL,
        [Parameter(Mandatory=$true)] [string] $GroupName
    )
 
    Try {
        #Get credentials to connect
        $Cred= Get-Credential
        $Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)
 
        #Setup the context
        $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
        $Ctx.Credentials = $Credentials
        $Web = $Ctx.web
 
        #Get the Folder
        $Folder = $Web.GetFolderByServerRelativeUrl($FolderURL)
        $Ctx.Load($Folder)
        $Ctx.ExecuteQuery()
     
        #Break Permission inheritence - Keep all existing list permissions & Don't keep Item level permissions
        $Folder.ListItemAllFields.BreakRoleInheritance($True,$False)
        $Ctx.ExecuteQuery()
        Write-host -f Yellow "Folder's Permission inheritance broken..."
      
        #Get the SharePoint Site Group object
        $Group =$Web.SiteGroups.GetByName($GroupName)
        $Ctx.load($Group)

        #Get permissions assigned to the folder
        $Ctx.Load($Folder.ListItemAllFields.RoleAssignments)
        $Ctx.ExecuteQuery()

        #Check if the Group has permission on the list
        [Bool]$GroupFound = $False
        ForEach($RoleAssignment in $Folder.ListItemAllFields.RoleAssignments)
        {
            $ctx.Load($RoleAssignment.Member)
            $Ctx.ExecuteQuery()

            #remove Group permission from folder
            If($RoleAssignment.Member.LoginName -eq $Group.LoginName)
            {
                $Folder.ListItemAllFields.RoleAssignments.GetByPrincipal($Group).DeleteObject()
                $Ctx.ExecuteQuery()
                $GroupFound = $True
                Write-host "Group Permissions Removed from the List Successfully!" -ForegroundColor Green  
            }
        }
        #If Group doesn't exist in list permissions
        If($GroupFound -eq $False) { Write-host "Group Not found in List Permissions!" -ForegroundColor Red}
    }
    Catch {
       write-host -f Red "Error Removing Group permissions from the Folder!" $_.Exception.Message
    }
}

#Config Variables
$SiteURL="https://crescent.sharepoint.com"
$FolderURL="/Project Docs/Active"
$GroupName="Team Site Visitors"

#Call the function to remove Group permissions from a list
Remove-SPOGroupPermissionsFromList -SiteURL $SiteURL -FolderURL $FolderURL -GroupName $GroupName

This Removes SharePoint Online group from folder permissions using PowerShell. Here is my another post on granting permission to SharePoint Online Folder using PowerShell: Set Folder Permissions in SharePoint Online using PowerShell

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