Troubleshoot Microsoft Outlook running slow or locking up

Troubleshoot Microsoft Outlook running slow or locking up

Microsoft Outlook running slow or locking up? This article can help with some troubleshooting advice

Table of Contents:

  1. Overview
  2. Try and open Outlook in Safe Mode
  3. Use scanpst.exe to fix Outlook Data File errors
  4. Repair the Outlook Profile
  5. Create a new Outlook Profile
  6. Repair Outlook via the Installer

1. Overview

When the Outlook program suffers from performance issues, it can be caused by several issues.

  • A corrupt or damaged PST File
  • An Outlook Add In, not functioning
  • A Corrupted Outlook profile
  • A Problem with the Outlook application

You can try some of the steps below to try and resolve this issue.

Caution: These instructions are aimed at Advanced Users, be careful when following these steps as potential loss of data and corruption of the Windows operating system can occur.

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2. Try and open Outlook in Safe Mode

Try and open Outlook in Safe Mode

  1. To start in Safe Mode, you can hold down the CTRL key when opening Outlook. (Keep holding it until message appears), or Click Start, In the Search or Run box, type outlook.exe /safe and press Enter

  2. If Outlook is slow or locks up whilst in Safe Mode, then it is very likely that an Add In could be causing the issue. In Outlook, click File, Options, then click Add In’s. At the bottom, where it says "Manage", click Go and in the next screen, remove the check marks

  1. Disable all your add-ins. After this, you can start Outlook normally again and see if it works now. If so, you can enable them one by one until Outlook fails again. The add-in you last enabled is most likely the cause of your issue. Uninstall or reinstall this add-in

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3. Use scanpst.exe to fix Outlook Data File errors

If disabling Add Ins in Outlook while in Safe Mode, does not resolve the performance issues, it is most likely that a corrupted PST file or profile is causing the issue.

The PST or personal storage folder, also known as a .pst file is where Outlook stores messages, contacts, appointments, tasks, notes, and journal entries

  1. Locate your PST file by opening Mail in Windows Control Panel. Click the Data Files button.

  1. If there is more than one PST file, look for the one with the checkmark. This is the default.

  1. Navigate to the path shown in the Data Files window. Eg. C:\Users\johnxxxxx\AppData\Local\Microsoft\Outlook

  2. You may need to "Show hidden files, folders and drives" and Untick "Hide extensions for known file types"
    See Microsoft Article - Show hidden files External Link for info on how to change these settings.

  1. It is advisable to save a backup copy of the PST file to safe location or removable storage

  2. Rename the .pst extension to .psp

  3. Try and open Outlook again and click OK twice when prompted during start up. This will create a new PST file. If Outlook opens successfully and there are no performance issues, then it suggests a problem with the original PST file.

  4. If however, the new generic PST file hows the same issues, then it is either a corrupt profile or Outlook is damaged. Move onto the next Repair the Outlook Profile section.

  5. Rename the .psp file back to .pst

  6. Attempt to run the scanpst.exe tool on the original file and test.

    Note: Outlook should NOT be running for this process.
    1. The location of scanpst.exe depends on your version and language of Outlook.
      • Outlook 2016
        32-bit Windows; C:\Program Files\Microsoft Office\Office16\
        64-bit Windows; C:\Program Files (x86)\Microsoft Office\Office16\
      • Office 365 / Outlook 2016 Click to Run
        Any Windows; C:\Program Files\Microsoft Office\root\office16\
      • Outlook 2013
        32-bit Windows; C:\Program Files\Microsoft Office\Office15
        64-bit Windows; C:\Program Files (x86)\Microsoft Office\Office15
      • Outlook 2010
        32-bit Windows; C:\Program Files\Microsoft Office\Office14
        64-bit Windows; C:\Program Files (x86)\Microsoft Office\Office14
    2. Double click on the tool icon

    3. Browse to the PST file that needs to be repaired

    4. When the scan is done and errors have been fixed, run scanpst.exe again at least 3 times

  7. Try opening Outlook again, if there are still problems with the PST file you can attempt further recovery by following the instructions in this Microsoft Article: Repair Outlook Data Files (.pst and .ost) External Link

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4. Repair the Outlook Profile

If Outlook shows the same performance issues with a generic PST file, then it is may be that it has a corrupted profile you can attempt to Repair it from within Control Panel.

  1. In Control Panel, select Mail, then click on E-mail Accounts

  1. In the Account Settings dialog box, on the E-mail tab, highlight your account, and then click Repair

  1. Follow any prompts from the repair wizard

  2. Click on the Finish option. When the repair is done, restart Outlook

Another option at this stage is to copy the existing Profile and see if that will open.

  1. In Control Panel, select Mail, then click on Show Profiles

  1. Click on Copy, enter a new name for the profile ie. add a 1 at the end

  2. Select your new profile from the drop down box, below the "Always use this profile" radio button, then click OK.

  1. Try re-starting Outlook

  2. If there is still a problem, try moving onto the next Create a new Outlook Profile section.

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5. Create a new Outlook Profile

If Outlook continues to have performance issues with a generic PST file, and the Copy and Repair functions have failed then you can try creating a new profile.

  1. In Control Panel, select Mail, then click on Show Profiles

  1. Click on Add, enter the name of the new profile

  2. Before selecting OK, select "Prompt for a profile to be used"

  1. Start Outlook, and select the new profile

  2. If the new profile allows Outlook to to perform normally, you can look at moving your data across to the new profile

  3. This Microsoft Article has further information:
    Move Outlook information to another computer that has Outlook 2010 installed External Link

If Outlook will still continues having issues move onto the nest section: Repair Outlook via the Installer

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6. Repair Outlook via the Installer

If none of the above steps are successful, then it is likely that Outlook is damaged. You can attempt to repair Outlook by choosing Change in Programs and features or Add or Remove Programs (XP).

If this and the above methods fail then you will have to uninstall and reinstall Outlook/Office.

For further information please follow the relevant links below.

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Article ID: SLN284173

Last Date Modified: 05/17/2017 06:57 AM

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