Fix Outlook error OST cannot be opened

Error : the set of folders cannot be opened. the file .ost is in use and cannot be accessed

"Outlook OST cannot be opened"- [Solved]

If you are having issues with MS Outlook, or if you are unable to access an Outlook OST file, or if the.ost file cannot be opened, you should try the following solutions. If you want a direct method, you can go with EdbMails OST recovery and converter tool to fix all of the errors and convert the OST file to PST.

How to resolve the issue Outlook OST cannot be opened?

The most likely reason for the error is that your OST file is orphaned or damaged (corrupted) as a result of improper synchronization with your online email account. This renders the OST file inaccessible and Outlook throws the error “The file .ost cannot be opened”. Follow some simple methods to resolve the issue.

• Method 1: Close Outlook and terminate all Outlook-related processes.
• Method 2: Turn off Cached Exchange Mode in Outlook
• Method 3: Convert the corrupted OST to Outlook PST
• Method 4: Install the latest version of MS Outlook
• Method 5: Create a new profile on Outlook
• Method 6: Close and Restart Outlook in Safe Mode
• Method 7: Disable Outlook-Add-ins that may cause conflicts
• Method 8: Repair the OST file and convert to PST using EdbMails

• Method 1: Close Outlook and terminate all Outlook-related processes

  Steps to perform the task:

  1. Close your Microsoft Outlook safely.
  2. Right click the taskbar and select the "Start Task Manager"
  3. Choose the "Processes" tab.
  4. Look for "Communicator", "Lync", "ucmapi" or "Outlook.exe". If you find it, right-click and click the "End Task" button.

• Method 2: Turn off Cached Exchange Mode in Outlook

  1. Close Microsoft Outlook if it is running
  2. Go to "Control Panel", Search for "Mail" and click on "Mail".
  3. Click the "Email Accounts..." button and choose the "Email" tab.
  4. Click the Exchange account, and then click Change.
  5. Under Offline Settings, Uncheck the "Use Cached Exchange Mode" >> Select "Next" >> "Finish".
  6. Exit, and then restart Outlook.

• Method 3: Convert the corrupted OST to Outlook PST

  If you have Outlook 2010 or later, you will be unable to recover the OST file using ScanOST. In case your offline Outlook Data File (.ost) has local data that is not present on the server, we recommend that you export the data to an Outlook PST file, and then you delete your offline Outlook Data File (.ost). After the data is downloaded from the Exchange server, you can import the Outlook PST file into the new offline Outlook Data File (.ost). During the import, you can exclude any duplicate data from the Outlook PST file.

  To export the offline Outlook Data File (.ost) to .pst file follow these steps

  1. Click on 'File' in Outlook, click 'Open & Export' > click 'Import/Export'

     

  2. Select 'Export to a File' and click 'Next'
  3. Select 'Outlook data file (.pst)', and then click 'Next'

     

  4. Select the folders you wish to export to PST.

     

  5. Select the option 'Do not import duplicates', and then click Next'

     

  6. Select the destination folder you would like to save the PST file and click 'Finish'.

• Method 4: Repair MS Outlook or install the latest version

  If you are using an outdated or an old version of Outlook (such as 2010, 2013), you may encounter such errors. Run an auto repair on Outlook or install the latest version of MS Outlook such as 2016 and 2019 and ensure that you also have the latest updates.

• Method 5: Create a new profile on Outlook

  You may get OST file related errors if you’re encountering issues with your Outlook profile. In such cases, remove your Outlook profile and allow Outlook to automatically add and set up a new profile for you.

   To remove the Outlook profile, go to File in Outlook > Account Settings > Manage Profiles > Show Profile > Remove the profile.

   See how to add a new Outlook profile from the Control panel.

  Remember that this method may not completely restore the changes made in your local OST file.

• Method 6: Close and Restart Outlook in Safe Mode

  When Outlook fails to open due to virus or malware infection, it makes sense to open it in safe mode and check if you can resolve the OST file opening issue.

  Press 'Ctrl +R' on your Windows computer and type 'outlook.exe/safe' to open Outlook in safe mode.

• Method 7: Disable conflicting Outlook Add-ins

  Certain Add-ins may cause conflicts with Outlook and prevent the OST file from opening. The following steps describe how to disable the add-ins.

  1. Open Outlook in safe mode as outlined in the previous step
  2. Now click on 'File' in MS Outlook and go to 'Options'.
  3. Under Options, click on 'Add-ins' and make sure that the 'COM Add-ins' are selected at the bottom.
  4. Click 'Go' and ensure that you 'disable/uncheck' all the Add-ins.
  5. Restart Outlook in the normal mode and check whether you get the error again. If there are no errors check which Add-in was causing the issue by enabling them individually and removing them.

     

• Method 8: Repair and convert the OST file to PST using EdbMails

  EdbMails OST to PST converter can safely recover an OST file that is corrupted or fails to open. You can open and view an OST file including emails, contacts, notes, tasks, folders and other data that you want to recover. Download and install the application on your computer to recover and convert your OST files.

  1. Start EdbMails and select the offline OST file that you want to convert
  2. Preview the individual folders, emails, messages, contacts,
  3. Select the mailbox items to convert to the PST file.
  4. Browse the location to save and click 'Export to Outlook PST'

     

Can EdbMails repair and recover OST files?

Yes!. Although we discussed the manual methods (from 1-6) for recovering the OST and resolving the error, they are not tried and tested for all scenarios. EdbMails is a professional and automated solution for recovering OST from all of the errors listed below, as well as assisting you in migrating your data to Office 365 / Exchange without data loss. You can even recover oversized files and use the various filter options to export only the items you require.

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