We have recently rolled out Exchange 2013 + Outlook 2013 across our business, and have just finished migrating users over to this. One of our machine which has 20GB Email (automated emails for logging) takes ages when creating a rule within either Outlook (when you click Add it says Updating Folders... and takes over 10 minutes per rule.

Running the same process through OWA takes about 5-10 minutes per rule that we try and create (there are currently around 250 rules already).

My query is:

  • Is this due to the amount of email, or number of current rules (or a mixture of both)?
  • Is there any way to resolve this, or has anybody else encountered this?

Thanks in advance

  • Having created many rules in my relatively new mailbox all on the same day, I can say that the number of rules on the mailbox is what made my rule creation process slow down. The first five rules I created didn't take that long. Each rule after that point took longer and longer and longer to finish creating. I have about 20 rules and I just stopped creating them and I sort some of my mail manually. Sadly I haven't come up with a workaround or mitigation for the issue yet. Oh yeah my exchange server is actually Office 365, so it might be more of an Outlook issue. Jan 9, 2018 at 20:17

1 Answer 1


That's a pretty unusual environment: tons of rules and very large mailbox sizes. Outlook performance deteriorates hard when you have more than 5-10K items in a single folder. The item size is irrelevant; the item count is what matters. You might get better performance from using the New/Get/Set-InboxRule cmdlets.

  • This information is correct (although I think Microsoft claims to have reduced or fixed the performance issue over 10k items in later version of Outlook), but I have the same experience in an inbox with only 2,600 items, so I'm not sure the item count is related to the rule creation performance issue.. Jan 9, 2018 at 20:14

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