You can do this first by searching it in the SharePoint ClientBrowser and then use a powershell script to delete it.
function Get-SPOListEventreceivers
{
param (
[Parameter(Mandatory=$true,Position=1)]
[string]$Username,
[Parameter(Mandatory=$true,Position=2)]
$AdminPassword,
[Parameter(Mandatory=$true,Position=3)]
[string]$Url,
[Parameter(Mandatory=$true,Position=4)]
[string]$ListTitle,
[Parameter(Mandatory=$true,Position=5)]
[GUID]$EventReceiverGUID
)
$ctx=New-Object Microsoft.SharePoint.Client.ClientContext($Url)
$ctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Username, $AdminPassword)
try
{
$ctx.ExecuteQuery()
} catch [Net.WebException]
{
Write-Host $Url " failed to connect to the site" $_.Exception.Message.ToString() -ForegroundColor Red
}
$ctx.Load($ctx.Site)
$lista=$ctx.Web.Lists.GetByTitle($ListTitle)
$ctx.Load($lista)
$ctx.ExecuteQuery()
$recevery=$lista.EventReceivers
$ctx.Load($recevery)
$ctx.ExecuteQuery()
Write-Host "Found " $recevery.Count " receivers in " $lista.Title
$recevery.GetById($EventReceiverGUID).DeleteObject()
try
{
$ctx.ExecuteQuery()
Write-Host "receiver removed"
}
catch [Net.WebException]
{
Write-Host "Failed to delete the receiver" $_.Exception.Message.ToString() -ForegroundColor Red
}
}
# Paths to SDK. Please verify location on your computer.
Add-Type -Path "c:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "c:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"
# Insert the credentials and the name of the admin site
$Username="spadmin@xxx.onmicrosoft.com"
$password = "$xxxx"
$url = "https://xxxx.sharepoint.com/sites/S046WW16776"
$AdminPassword=Read-Host -Prompt "Password" -AsSecureString
$Url="https://xxx.sharepoint.com/sites/S046WW16776"
$ListTitle="Project Metadata"
$EventReceiverGUID="8ded46d9-6b87-4dac-9532-64d013122e92"
Get-SPOListEventreceivers -Username $Username -AdminPassword $AdminPassword -Url $Url -ListTitle $ListTitle -EventReceiverGUID $EventreceiverGUID
