NEO reports that a Personal Folders (PST) file is locked by another application

Topic T1142 Applies to All NEO products


Outlook or NEO reports that a Personal Folders (PST) file or archive PST file is locked by another application.


NEO is a third-party add-in to Outlook and relies upon Outlook to handle all e-mail message transport, editing, printing and other functions. NEO does not communicate directly with any Outlook message store, whether PST file, archive PST file, Exchange Server mailbox or OST file. All communication NEO does with the Outlook message stores is through Outlook. NEO sends message manipulation or message transport events to Outlook via the Microsoft MAPI interface, which Outlook receives. Outlook then processes the direct message manipulation or transport on NEO's behalf. As a result of this, NEO can never have a PST file locked since it never directly accesses them.


To resolve this problem, examine other software that may directly access your PST stores and in doing so would appear to have them locked to other applications, such as:
To test if a file is really locked, you can use a trick. To do this, you must first close Outlook, NEO and all other known e-mail applications, such as ActiveSync, etc. Locate the path to the PST files. Use Windows Explorer to visit the folder where the PST file is and try renaming the PST file. If you can rename it, then it isn't locked.

If a file is locked, you will need to find which application has the file locked and shut it down. It may take some time for Outlook to release (unlock) the PST file after Outlook was closed (up to a minute, in some cases). If Outlook had previously crashed, the PST files may still be locked by a hanging Outlook process and only manually using the Task Manager to end the Outlook process or a reboot will help. If all this doesn't help, please use the freeware program Process Explorer to help find out which application has your file locked.

Last updated: 15 Feb 2005