Using Office 365 ProPlus on older, unsupported operating systems may cause performance and reliability issues over time. This includes using Office 365 ProPlus on a Windows operating system that is currently in support.

Because Office 365 is governed by the Modern Lifecycle Policy, customers are required to stay current as per the servicing and system requirements for the product or service. Select Outlook Advanced Diagnostics, and then select Run when you are prompted by your browser.As announced previously, Windows 7 will be out of support after January 14, 2020. For Outlook 2010, see How to troubleshoot performance issues in Outlook.For Outlook 2010 and later versions, see Outlook not responding error or Outlook freezes when you open a file or send mail.Try the methods from the following articles, as appropriate for the version of Outlook that you're running: Test to learn whether the issue is resolved. For more information, see How to install the latest applicable updates for Microsoft Outlook (US English only). Make sure that the latest updates for Outlook are installed. This includes issues that affect your local proxy server, firewall, or Internet service provider. If other customers are experiencing the issue, the issue should end when the service-interrupting event is resolved.Īlso, determine whether any local network issues might be causing the problem. In this case, sign in to the Microsoft 365 portal by using your administrator credentials, and then select service health to determine whether other customers are experiencing the same issue. This issue may be caused by an Exchange Online server issue. Outlook is retrieving information from the server Frequently, you receive the following warning message: Outlook responds slowly when you try to insert an attachment.When you send an email message, the message sits in the Outbox folder for a long time.Outlook responds slowly when you try to open email messages.

When you use Microsoft Outlook together with Microsoft 365, you experience one or more of the following symptoms:

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