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Summary: This article discusses the transition options for Outlook for Mac, highlighting its features and potential errors like Error code 17199. It offers expert solutions to resolve this error, including steps to manage Outlook emails, check web connectivity, validate credentials, and address OLM file corruption. The article also recommends Kernel for OLM to PST Converter as a reliable tool for resolving Outlook for Mac errors and data recovery.

If you’re feeling weary of the older iteration of Outlook, it’s worth noting that Mac users now have the ability to seamlessly transition between the new and classic versions via a toggle within the application. This enhancement ensures that Mac users will enjoy a refreshed aesthetic and an enhanced user interface, complete with upgraded features like an advanced Search, Event Scheduling, and integration with Microsoft 365 Groups. Starting from February 2022, users operating macOS version 10.14 (Mojave) and onwards will find the new Outlook for Mac set as the default option.

Microsoft’s Outlook for Mac has expanded the accessibility of Windows-based applications to the Mac OS environment. This means that Mac OS users can now seamlessly configure their emails in Outlook for Mac, facilitating improved email communication. The software’s user interface is tailored to suit MacOS, ensuring a seamless experience, and all functionalities are optimized for effective email management. Nevertheless, there might be occasional technical hiccups. In this guide, we’ve compiled expert strategies to address any errors encountered in Outlook for Mac.

Outlook for Mac employs the OLM format to store all mailbox items. Each time you establish an account within the application, a corresponding OLM file is generated. While you typically won’t need to directly engage with the OLM file, understanding its location is crucial if you wish to back up your account.

Locating and accessing OLM files is typically trouble-free, barring any unforeseen malevolent incidents that might cause damage. You can pinpoint the location of the OLM file on your Mac OS using the following links:
Outlook for MAC 2011

Users/Username/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Database

Outlook for MAC 2016

Users/username/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile

Discussing corruption, one can observe that various factors like power outages, hard drive malfunctions, worm intrusions, Exchange crashes, and Apple OS errors can lead to significant damage to the OLM database, severely impacting email communication. According to the experiences of numerous Mac Outlook users, Error code 17199 is the most prevalent issue they encounter, causing temporary or even permanent disruptions to Outlook services.

Fixing the Outlook for Mac error code 17199

Prior to encountering Error code 17199, users may have attempted to remove a lingering message from the Outbox that stubbornly refused to be deleted. This scenario might feel familiar if you’ve ever tried to delete a hefty message laden with numerous attachments that simply wouldn’t budge. The moment you succeed in deleting this lingering message, which persists as a spectral email within the Outbox, you may be confronted with the dreaded message: “An unknown error has occurred in Outlook – Error code 17199.” Subsequently, all email communication through the Outlook for Mac email client can become congested due to the aforementioned incident. In such situations, the top priority should be to manage and prevent OLM corruption to mitigate these error-related issues.

Various approaches to resolve error 17199: “An Unknown Error Has Occurred In Outlook.

Solution 1- Send Outbox Emails to Trash

To completely remove all of your Outlook emails, you should proceed with the following steps:

Step 1: Open your Outbox folder then delete all emails from it.

Step 2: Now, select on Send or Receive option.

Step 3: And, check whether the error is fixed, if it still exists then follow the next step.

Solution 2- Delete Ghost Emails from Outbox

If you find it challenging to manually remove all emails from Outlook’s Outbox, follow these steps:

  1. Navigate to Applications -> Utilities and launch the AppleScript Editor.
  2. In the AppleScript Editor, specify the following command, and then click Run.
tell application “Microsoft Outlook
delete every message of outbox
end tell
Solution 3- Ensure the Availability of Web Connectivity

Examining network and web connectivity is crucial for maintaining Outlook for Mac email communication services. Begin by verifying your ability to connect to web services through a standard web email account login. If everything appears to be functioning properly, proceed to review your other Outlook settings.

Solution 4- Validate & Reconfigure the Outlook Credentials

One unquestionable cause for encountering the “An unknown error has occurred in Outlook” with Error code 17199 may stem from having incorrect user account credentials in Outlook for Mac. If there is any uncertainty regarding the accuracy of the username and password, it is advisable to rectify the situation by following these steps to reconfigure the settings:

  1. Launch the Outlook for Mac application.
  2. Click Tools, and then Accounts.
  3. Navigate to the left panel, and then select the current user account.
  4. Specify the accurate email address and password.
  5. Inspect the settings under Incoming server and Outgoing server.
  6. Close the application and restart Outlook to check if it works.
Solution 5- Try Renaming existing Identity/ Create the New One

If despite attempting the aforementioned solutions, you find yourself unable to resolve the error, consider renaming an existing identity. Alternatively, you can attempt to generate a new identity using either the MS Database Utility or a built-in application within MS Office.

When addressing Error code 17199, it is crucial to verify the integrity of OLM data files. These files may become compromised due to disruptions, either temporary or permanent, in the Send/Receive process. Although the Microsoft Database Utility can be employed to reestablish the Outlook ID and address various corruption issues during preventive measures, it does not assure flawless restoration of OLM data files from such situations. To effectively delve into the heart of OLM corruption and execute an automated recovery, one must turn to a third-party OLM recovery software.

Solution – Kernel for OLM to PST

Kernel for OLM to PST is an exceptional application designed to eliminate any type of OLM corruption and offer a secure backup solution to ensure seamless OLM to PST migration. This software is equipped with specialized migration capabilities, allowing you to store repaired OLM emails on various email servers, cloud services, or web-based email applications. Additionally, it provides unmatched compatibility with the latest versions of MS Outlook 2019/2016, Outlook for Mac 2019/2016, and Windows 10 editions.


To sum up, we’ve thoroughly addressed the underlying causes of error code 17199 in Outlook for Mac. Furthermore, we’ve provided insights into potential solutions to rectify this issue. If attempts to reconfigure settings, as outlined in this post, have proven unsuccessful, it indicates a more significant concern. Similar to other data files, OLM data files are susceptible to corruption. In cases of severe damage, even built-in tools like the MS database utility may be ineffective. In such critical situations, a dependable external tool becomes essential.

While there are numerous tools claiming to fully restore damaged OLM files, most fall short. Kernel’s OLM to PST tool, a reputable name in data recovery, stands out as an exceptional solution. It swiftly addresses various forms of OLM corruption and facilitates the seamless import of OLM files into Outlook 2019, 2016, and 2013. Furthermore, the tool boasts migration capabilities, allowing users to store repaired OLM email items on both email servers and cloud services. In essence, Kernel for OLM to PST encompasses a range of invaluable features to assist users in overcoming error code 17199.

Kernel for OLM to PST