This article will help you diagnose and resolve issues where users of Microsoft Office Outlook experiences poor performance when they work with Microsoft Exchange Server 2007/2010/2013/2016.
When this issue occurs, Outlook users may receive one of the following messages:
- Requesting data from Microsoft Exchange Server.
- Outlook is retrieving data from the Microsoft Exchange Server.
- Trying to connect.
- Not Responding.
Here are the recommended item counts from Microsoft:
- Exchange 2007 No more than 50000 messages in a single folder
- Exchange 2010/2013/2016 No more than 100000 messages in a single folder.
The recommended number of items in a folder depends on several factors. These factors include the client's proximity to the server, the storage infrastructure, the load on the hard disks, the number of users, and the number of restricted views. We recommend that you maintain no more than 5,000 items in a folder. Below you will find some ways to do that as well as some other ways to improve Outlook performance.
- Archive your data Read the Knowledge Base article on Overview Of Data Archiving Options for information on various archiving options, both client-side and server-side.
- Outlook 2013/2016 - Mail to keep offline Outlook 2013/2016 users may choose how much data they would like to store in their OST file. For example, you can set it to keep 6 months worth of mail offline. It doesn't mean all the other data is inaccessible, it just means that all the other data is accessed in the Online mode. It doesn't affect any Outlook functionality, e.g. when searching, you are still searching through your whole mailbox.
- Repair your OST file often If you have a large OST file, it would be a good idea to repair it often. Read the Knowledge Base article on How To Use the Inbox Repair Tool (scanpst.exe)
- Disable unnecessary add-ins Review the list of add-ins that are running in Outlook and disable the unnecessary 3rd-party ones, like iTunes, antivirus add-ins, Business Contact Manager or ACT!.
- Outlook 2010/2013/2016: File > Options > Add-ins
- Outlook 2007: Tools > Trust Center > Add-ins