I have taken over from a colleague the monitoring of a large inbox hosted on outlook 365. the inbox has accumulated about 100,000 emails. mostly the messages are from two monitoring accounts that report system up / system down sort of activity in an email.

I tried the following to no avail:

1) create rule to delete all messages from a particular address. the rule would take about 16 days to complete running inside outlook 2016

2) I sorted the inbox by the "From" and tried to delete the group of about 50,000 emails. outlook hummed along and reported that it would take about 8 minutes to process. it ran without incident, but at the end none of the emails were actually deleted out of the inbox.

any help or tips on how I might slay this demon?


I found out the there is a really good way to do this. Outlook 365 has in the web portal version of office a "sweep" rule that can run periodically through the inbox cleaning up email. The useful option I found was to delete all email older than days from a particular recipient. 

I was able to clean up my inbox without having outlook running on my desktop in a matter of hours.

How to set up a server side Sweep rule for outlook 365

  • 1
    Nicely done. I figured there had to be some way to do this in the web interface. Generally speaking the closer to the server you get the faster things will run, and I'd guess all the communication between your Outlook client and the O365 servers accounted for most of the slowness in the processes you were running. – music2myear Jan 5 '17 at 20:26

The closer to the server, the faster things will run. So if you have O365 web access, while the interface may be less friendly, it should run these processes faster and more reliably.

I haven't worked with the Office 365 Web Interface, but you can build simple rules in Outlook Web Access, and if you can build a similar rule in O365 and run it in the web interface, it may run much more quickly (or at least not bog down your personal Outlook quite so much).

If this doesn't work or isn't an option, getting a spare computer to open just this mailbox for a little while and running the rule in it would also work.

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