How to Fix Outlook PST is in use and cannot be accessed (Microsoft Outlook)
Quick Answer
The error "Outlook PST is in use and cannot be accessed" indicates that the Outlook data file (.pst) is currently locked by another process or application, preventing Outlook from accessing it. The fastest fix is to ensure all instances of Outlook are closed and restart the application.
What Causes This Error
- Outlook application is still running in the background, even after being closed.
- Another program, such as an antivirus scanner or backup utility, is accessing the PST file.
- Improper shutdown of Outlook, leading to a corrupted or locked PST file.
- Multiple Outlook profiles are attempting to access the same PST file simultaneously.
- Add-ins within Outlook are interfering with file access.
- System issues or file system errors are preventing access to the PST file.
Step-by-Step Fixes
1Close All Outlook Processes to Resolve 'Outlook PST is in use and cannot be accessed'
- Save any open work in Outlook and attempt to close the application normally.
- Open the Task Manager by pressing Ctrl+Shift+Esc or right-clicking the taskbar and selecting 'Task Manager'.
- Navigate to the 'Processes' tab (or 'Details' tab in newer Windows versions).
- Look for any processes named 'Outlook.exe' or 'Communicator.exe' (if Microsoft Lync/Skype for Business is integrated).
- Select each identified process and click 'End task'. Confirm if prompted.
- Attempt to open Outlook again.
2Disable Antivirus or Backup Software Temporarily
- Locate your antivirus software icon in the system tray (bottom right of your screen) or open it from the Start menu.
- Right-click the icon and look for options like 'Disable Protection', 'Pause Protection', or 'Exit'. Select the appropriate option to temporarily disable it.
- If you use backup software that targets your Outlook data files, temporarily pause or exit that application as well.
- Attempt to open Outlook. If it opens successfully, re-enable your antivirus/backup software and consider adding an exception for the PST file location in its settings.
3Run Outlook in Safe Mode
- Close all instances of Outlook.
- Press the Windows key + R to open the Run dialog box.
- Type 'outlook.exe /safe' (without quotes) into the dialog box and press Enter.
- If prompted, choose your profile and click 'OK'.
- If Outlook opens successfully in Safe Mode, it suggests an add-in is causing the issue. Proceed to disable add-ins from within Outlook's Safe Mode session.
4Repair Outlook Data Files (.pst and .ost)
- Close Outlook and any other applications that might be accessing the PST file.
- Navigate to the following path in File Explorer: C:\Program Files (x86)\Microsoft Office\root\Office16 (for Office 2016/2019/365 64-bit) or C:\Program Files\Microsoft Office\root\Office16 (for Office 2016/2019/365 32-bit). The 'Office16' folder name may vary based on your Office version (e.g., 'Office15' for Office 2013, 'Office14' for Office 2010).
- Locate and double-click 'SCANPST.EXE' to open the Inbox Repair Tool.
- Click 'Browse' and navigate to the location of your PST file (typically C:\Users\YourUsername\Documents\Outlook Files\outlook.pst). Select the file and click 'Open'.
- Click 'Start' to begin the scan. If errors are found, click 'Repair' to fix them. Repeat the scan and repair process multiple times if necessary until no more errors are reported.
- Attempt to open Outlook normally after the repair is complete.
Advanced Fixes
Create a New Outlook Profile
- Close Outlook.
- Open the Control Panel. Change 'View by' to 'Large icons' or 'Small icons' and find 'Mail (Microsoft Outlook)' or 'Mail (32-bit)'. Click it.
- In the Mail Setup dialog box, click 'Show Profiles...'.
- Click 'Add...' to create a new profile. Give it a descriptive name and click 'OK'.
- Follow the on-screen instructions to configure your email account(s) within the new profile. You can choose to connect to your existing PST file or create a new one.
- Once the new profile is configured, select 'Always use this profile' and choose your new profile from the dropdown menu, or select 'Prompt for a profile to be used' and choose the new profile when launching Outlook.
- Restart Outlook to use the new profile.
Check for Corrupt User Profile
- Create a new local user account on your Windows system. Go to 'Settings' > 'Accounts' > 'Family & other users' > 'Add someone else to this PC'. Follow the prompts to create a new user.
- Log out of your current user account and log in with the newly created user account.
- Attempt to open Outlook and configure your email account under this new user profile. If Outlook functions correctly, your original user profile may be corrupted.
- If the new profile works, you may need to migrate your data and settings to the new profile or contact IT support for further assistance with your original profile.
Frequently Asked Questions
What is a PST file?
A PST (Personal Storage Table) file is a data file used by Microsoft Outlook to store copies of messages, calendar events, contacts, and other items on your computer. It is the primary data file type for POP3 accounts and can be used for archiving with other account types.
Can I have multiple PST files?
Yes, Outlook allows you to have multiple PST files. You can create additional PST files for archiving old emails or organizing specific types of data. Each PST file can be opened and accessed within Outlook, though only one can be set as the default data file.
Why does my PST file get corrupted?
PST files can become corrupted due to several reasons, including improper Outlook shutdowns (e.g., power outage, system crash), large file sizes exceeding recommended limits, hardware failures, malware infections, or conflicts with other software accessing the file. Regular backups and proper Outlook closure can help prevent corruption.
What is the difference between PST and OST files?
PST (Personal Storage Table) files store data locally and are primarily used for POP3 accounts and archiving. OST (Offline Storage Table) files are synchronized copies of your mailbox data from an Exchange, Microsoft 365, or IMAP server, allowing you to work offline. OST files are not meant to be opened directly or moved like PST files; they are recreated from the server if deleted.
How can I prevent this error from happening again?
To prevent the 'Outlook PST is in use' error, always ensure Outlook is properly closed before shutting down your computer. Avoid running multiple applications that might access the PST file simultaneously, keep your antivirus software updated with proper exclusions, and regularly run the Inbox Repair Tool (SCANPST.EXE) as a preventative measure.