What is OLK file Format?

Technical Detail of .olk File Extension

Developer Microsoft
File Category Outlook Database File
File Format .olk
Supporting Platform Mac OS X
MIME Type application/octet-stream
Format Type Binary

The OLK files are recognized as Outlook Address Book that contains contact information of an individual and Organizations as well. It is developed by Microsoft Corporation, which can store the name, email addresses, title and other contact detail for data management. OLK file extension is not familiar by most of the users, as contacts in Outlook program are mainly saved in PAB (Personal Address Book) files, whereas the email messages are stored in the OLM file. It is only a virtual address book file instead of a physical address book because Outlook cannot save the Address Book as files that are separately from a data store. On windows platform, OLK files can be opened and useful for mail merging and other document operations performed. Also, attachments are saved separately in another OLK format.

Types of Outlook Mac OLK File

Outlook 2011 for Mac used two types of OLK file, which are associated to store each mail i.e. OLK14Message and OLK14MSGSOURCE. OLK14Message can be defined as the storage of data file, which can manage all the desired information about the headers regarding the emails, which are collected in Outlook Mac 2011. However, this file does not have its own mail body instead; it can save all the header information only. The body of an email is stored in another OLK File format, i.e. OLK14MSGSOURCE. It can save the replica of all emails, which are available in Outlook 2011.

Different Variants of Mac OLK File Format

Yet, we only focussed on the message storing OLK14 file and message header storing OLK files also. However, there is not only one or two, but having multiple OLK files provided by Outlook for Mac client.

The messages are to be divided into many components all of them are saved with a unique file extension of OLK. Some of the variants of .olk file extension are listed below:

1: Category File: Category is being used for message tagging, contacts, calendars, or such other components. The file can contain the name and color by assigning a category. Such as files cannot be opened or stored by the users. This can easily generate some application and only readable files for reading the specific category. By default, some categories like Family, Personal, No Category, Holiday, and so on.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Signatures/

2: Calendar Event: This file means to save data content of the event(s) created by using Outlook calendar. An event consists the following information such as time, date, invitees and etc. In OLK Calendar event is used to save a copy of local cache of the created events even in such situations where the calendar that is stored remotely.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Events/

3: Contact File: The contact OLK file can easily store the information related to the contact including details like email address, name, and business information. This data information is entered on the Outlook interface and also used for saving the contact detail. No direct interaction is possible with the users after generating the OLK14CONTACT Mac by Outlook.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Contacts/

4: Email Message: The OLK14MSGSOURCE file contains the source data of particular mail for mentioning a message. The application can load this file while viewing the desired message. When the concentration is on reading an email then, the information from the OLK14MSGSOURCE file is loaded automatically by an application. Storing message and its source individually makes the client function more effectively.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Messages Source

5: Group File: The group file by Outlook for Mac 2011 is created to save the grouped contacts in a collection of data. This has been done for maintaining the collection of contacts in a well-organized way by a client.

6: Message File: OLK14MESSAGE file or the message file for Mac 2011 defines to save the header related information only. The application can use such file for reading the message details like header data but not the body of mail. Message overview must be taken on the front-end application by the users, through this file loaded by a client on the backend. These multiple files can read in fragments by using Apple based text editor.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Messages/

7: Signature File: OLK file for signatures, which stores email signature of Outlook for Mac account in HTML code. The files are saved and loaded automatically by an Outlook client, which may be inaccessible to all users via direct ways.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Signatures/

8: Mail Account: The contents are stored by this OLK file extension that consists mail account settings of the already configured profile, connection, and login information. The file has meant for storing the account related data, which allows the users to get their emails accuratly and perform the calendar synchronization too.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Mail Accounts/

9: Preferences File: OLK14 PREF file is meant for the storage of software related to the preferences, which specifies the settings for reading or composing each message also. Application being generated and readable files, this such OLK files are again inaccessible to the software.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Preferences/

10: Note File: OLK file for Note, which consists of a particular Note that was generated with the help of Notes component equipped in Outlook. Besides saving each note that were written by a user, the file can also store the formatting of a Note and may be used for Personal as well as Business notes created by the user.

Location: [user]/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Messages/

11: Task file: The OLK files are generated for Task, which contains the ‘To-do’ generated by the user on an application. This information shows the marking applied on messages flagged for the purpose of the outcome. The OLK14 TASK has auto-generated as soon as possible a new task is given by a user.


OLK files are the backend database files managed by Outlook for Mac 2011. The OLK14 file works on the database but unable on a data file as its Windows counterparts. Thus, the database requires many files, which supports to read the content when a user commands the application for performing various functions containing reading mails, notes, calendar, and more. Also, considering the various aspects of file format, we represent the entire information to let the users understand what is .olk File extension and its type in detail. However, we have discussed variants and how they are associated with the other file format and also mentioned its location where they are saved.