If you have a meeting that has been sent to many calendars across your organization but are not a delegate of those calendars then it can be a pain to successfully remove the meeting from multiple Exchange mailboxes.
With the command below in Exchange Powershell we remove a meeting from every calendar in your exchange organisation.
Get-Mailbox -ResultSize unlimited | Search-Mailbox -SearchQuery 'kind:meetings and Subject:"calendar meeting subject line" and Received:>"1/6/2016" and Received:<"14/6/2016" and Sent:>"1/1/2015" and Sent:<"12/1/2015"' -Deletecontent
In the example above we delete all calendar entries with the subject title of “calendar meeting subject line” – change that to your subject, we also specify that only remove the meetings that where arranged between particular dates.
This was tested in Exchange 2013 and 2016, if it works on previous versions then please comment below. Note: There is a limit 10000 mailboxes for this command. If you have to search through more mailboxes than this then you will need to use the new search compliance command in Exchange 2016.
New-ComplianceSearch -Name "RemoveCalendar1" -ExchangeLocation All -ContentMatchQuery "'calendar meeting subject line'"