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Outlook is one of the standard email clients used in the corporate world. With time, the performance of this powerful email client gets degraded due to some or other reason. This performance issue is found even in later versions like Windows 10 and 11.

We shall discuss some common fixes for Outlook running slow in Windows 10. Let us first understand the reason for the degraded performance of Outlook.

Reasons for the slow running of Outlook

  • Oversize PST file
  • Corrupt or damaged PST files. To improve Outlook performance, you can repair corrupt PST files and see whether Outlook regains its speed.
  • Oversize OST files. You can repair corrupt OST files and see if the Outlook performance improves or not.
  • Outdated Outlook version.
  • Virus and malware issues, faulty add-ins.
  • Corrupt emails or files.

Fix Outlook is running slow in Windows 10/11

If Outlook is running slow on Windows 11/10, you can try these fixes one after the other till the issue gets resolved.

Method 1: Open Outlook in safe mode

  • Press Windows key + R, type outlook.exe/safe, and press OK
  • Now open Outlook and click File.Click File
  • Select Options and then Add-ins.Select Options
  • Scroll down to Manage, select COM Add-ins, and click Go
  • Uncheck all the add-ins.Uncheck all the add-ins
  • Click OK.

Method 2: Repair the existing Outlook profile

Repairing a damaged Outlook profile can also be one of the solutions for the slow running of Outlook.

  • Open the Control Panel and select mail
  • Select Email Accounts.Select Email Accounts
  • Click on the Email tab, under Account Settings.Click on the Email
  • Select your profile and click on Repair.
  • Follow prompts on the Repair Wizard. Click Finish.
  • Restart Outlook once the repair is done.

Method 3: Create a new Outlook profile

  • After opening Mail from the Control Panel, click on Show on Show Profiles
  • Select the Add button and enter the name of the new profile.Select the Add button
  • Select a profile to be used and click OK
  • Restart Outlook with the new profile.

Method 4: Download all the Outlook items

You must download all the messages and attachments in Outlook when it is connected to IMAP or POP3. This will prevent syncing of Outlook with IMAP and POP3 every time opening a new mail. Continuous syncing also hampers Outlook’s functioning.

Method 5: Reduce Outlook Data

  • One of the major reasons for Outlook’s degraded performance is too much unnecessary data in Outlook.
  • Reduce calendars- Outlook extracts data from the internet, and one such least important data is calendars from different countries. Try to keep calendar data and a list of holidays only in the required country.
  • Archive inbox mailboxes- archive all mailbox items prior to the last two months. You can also set up Outlook in auto archive mode, which will prevent unnecessary piling of emails.

Method 6: Compact PST files

  • Go to File and select Account Account Settings
  • Click on Data files.Click on Data files
  • Select the data you wish to compact and select Settings.Select Settings
  • Under the General tab, click Compact Now. Then click Compact Now

Method 7: Repair using scanpst.exe

Outlook has an inbuilt Inbox Repair Tool that can repair small PST errors which might otherwise affect the working of Outlook.

  • Locate Scanpst.exe double click on it.
  • Browse the corrupt PST file under Inbox Repair Tool.Browse the corrupt PST file
  • Select the option Repair.Select the option Repair
  • Restart Outlook once the repair process is completed.

Method 8: Update Outlook

If your Outlook running slow issue still persists, then the next solution is to check for updates & if it exists, then you need to update Outlook to the latest version.

  • Access Outlook & go to the File menu. Tap on the tab Office Account.
  • Next, you need to click on the option Update Option. Select Update Now.update Outlook
  • Once the Outlook update is done, then you might fix the Outlook running problem.

Method 9: Use Third Party Software

This is the last yet perfect solution for Outlook running slow in Windows 10/11. One of the common reasons for the reduced performance of Outlook is corrupt PST files. These damaged PST files not only hamper Outlook progress but also worsen the situation. In this case, we have Kernel for Outlook PST Repair that recovers and retrieves damaged Outlook mailbox items. This includes emails, contacts, attachments, drafts, tasks, deleted items, and much more. You can use this tool to scan all your Outlook data while maintaining data integrity.


To prevent slow Outlook execution in Windows 10/11, ensure that Windows is updated and meets all hardware and software requirements. You must also try to keep the file size limit of OST and PST files up to 10GB. The Outlook PST Repair is one such a tool that guarantees improved Outlook performance and accuracy by repairing PST files.

Kernel for Outlook PST Repair