Resolve Outlook .ost Cannot Be Accessed Error

Microsoft Exchange Server uses an offline Outlook Data File (.ost). This type of data file is a copy of information saved on your mail server. OST files play a major role when there is limited network connectivity or server downtime issue. There are many reasons that can make your Offline Outlook Data folder (.ost) corrupted or damaged. Some of them are –

  • File system disaster may lead to loss of original OST file contents or it may overwrite with garbage data. And finally, the .ost file will contain invalid data
  • Virus or malicious software can infect and damage the .ost files or can also make them inaccessible
  • Synchronization between offline folders and server may also lead to many errors, including large numbers of conflict items, cannot open particular Outlook items, etc
  • Slow internet connection
  • Multiple users accessing the same .ost file simultaneously

These are some of the causes for Outlook .ost file cannot be accessed error. Before going to third party repair tools, it is suggested to try the below given quick fix methods:

  • Quit Outlook and restart it
  • Quit Outlook, restart your PC and then restart Outlook
  • Run the MS Outlook inbuilt utility called “OST Integrity Check”. However, this is available only in Outlook 2007 and lower versions. Here are the steps to use this utility:
  • Quit MS Outlook
  • Run SanOST.exe present in Outlook installation folder
  • In the window that opens, provide Outlook profile name when prompted
  • When asked to choose between “Work Offline” or “Connect”, choose “Connect”
  • Select from options “Scan all folders” or “Choose folder to scan” as per need
  • You can choose to “Repair Errors” if required and then click on “Begin Scan

One or the other alternative above is sure to resolve the OST error. However, if you’re not able to regain access to your mailbox even after these fixes, that could mean some major damage to the .ost file. In such situation, the best solution would be to convert your .ost file to .pst file. Try out Yodot OST to PST Converter tool to repair and convert Outlook OST file to PST.

Steps to solve OST error by OST to PST conversion:

#1.  Tap here to download and install Yodot OST to PST Converter application in your Windows PC

#2.  Launch it and follow the instructions provided

#3.  You will find two options in the main screen: “Open OST File” and “Find OST File”

#4.  Click “Open OST File” option if you are aware about its location otherwise select “Find OST File”

#5.  Browse for the target folder to save the converted file

#6.  Select “Convert” button to begin conversion process

#7.  The software starts converting the OST file, after completing the process you will get a message like “OST file conversion completed”

Yodot utility is developed to convert inaccessible OST file into an active Outlook PST file. It fixes Outlook error messages, Microsoft Exchange Server problems and other related issues. Outlook OST file objects such as emails, contacts, calendar items, reminders, notes, journals, etc are recoverable. It works flexibly with all Microsoft Exchange versions like MS Exchange 5.0, 5.5, 2000, 2003, 2007 and 2010. This application can be operated on different Windows versions such as Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, Windows XP, Windows 2003 and 2008.