OST file gets created when Cached Exchange Mode is turned on and serves as the mirror image of Exchange DB mailboxes on the local machine. A replica of the Exchange mailbox data gets stored on client machine. The data can be deleted or modified even when there is no connectivity persists with EDB account.
The modified items get synchronized with EDB account when a connection is retrieved with Exchange Server. Sometimes, the OST file turns into inaccessible mode and shows "Outlook OST file is in use and cannot be accessed" error.
There are different reasons responsible for the occurrence of this error message. This might takes place due to:
Several workaround and measures can be followed to eradicate the persisting Outlook OST file is in use and cannot be accessed error message. These include:
Solution #1: Running ScanOST.exe:
The issues with the Offline Storage Tables can be eliminated by executing 'OST Integrity Check' tool. The inbuilt utility helps in rectifying minor corruption issues with these files. The only limitation with this utility is that it cannot repair files with higher corruption extents.
Note: ScanOST.exe is available in Outlook 2007 and lower versions and is not provided in latest versions of the application.
Step-by-Step Description for Executing ScanOST.exe:
Note: If the checkbox associated to the 'Repair Errors' is not tick-marked, the tool will check the issues but will not execute the appropriate corrections.
Detect OST Storage Location:
The location for the OST file can be detected by following the given procedure:
However, if there is major corruption exists in the file, it is suggested to convert OST file to PST for removing the existing error message. The procedure to implement this task is described in the upcoming segment.
Solution #2: Convert OST to Outlook PST
Due to absence of 'OST Integrity Check' tool in Outlook 2010 and recent versions, Microsoft recommends to convert OST to PST for removing the associated issues. This can be done via 'Import & Export' Option available in the application.
Note: The above stated procedure applies to Outlook 2013 and 2010 versions. The overall conversion process may vary in lower versions of the application.
Though the procedure to run ScanOST.exe as well as to convert OST to PST is mentioned in this section, but these methods are associated with several limitations. They are quite lengthier and involve the possibilities of data loss. Manual conversion of offline files to Personal Storage Tables is not recommended as it might result in loss of crucial information stored in mailbox.
Moreover, the structure of email messages as well as the embedded attachments may lost their integrity while conversion. ScanOST.exe, the inbuilt utility, may help in removing minimal level corruption but is not helpful in eliminating higher level corruption issues. Moreover, the utility has been removed from the recent versions of the application. Therefore, the straight-forward and reliable third party tool can be utilized for getting rid of the OST error messages.
However, an easiest and simpler approach for rectifying "Outlook OST file is in use and cannot be accessed" error can be utilized to safeguard data from damage. RecoveryTools Exchange OST Recovery software can be employed for resolving OST related issues. The tool recovers offline file data and converts it to PST, EML, MSG and PDF format.