Kerio Outlook Connector is a Microsoft Outlook extension that you can use to manage Kerio Connect email, events, contacts, and tasks in Microsoft Outlook for Windows. The Offline Edition (KOFF) is the most commonly used as it allows offline editing and synchronizes all changes with Kerio Connect once the connection is restored.
- Using Kerio Outlook Connector
- Installing Kerio Outlook Connector
Using Kerio Outlook Connector
Kerio Connect provides several ways of accessing emails on a Windows device, from the Kerio Connect Desktop Client (KCC) to the use of IMAP or Active Sync with Outlook. Some users may find these options lack some of the standard features of a native Outlook Exchange connection.
For this reason, the Development Team created the Kerio Outlook Connector to fill this gap in functionality. Still, there are some Key Differences Between Offline Kerio Outlook Connector and a Native Outlook Exchange Connection that should be kept in mind when choosing to use KOC.
Note that Outlook for Mac 2011 and 2016 can connect with Kerio Connect natively through Exchange Web Services, so a similar macOS version of the Kerio Outlook Connector was not developed.
Optimizing KOFF Performance
While there are Outlook-specific settings that heavily impact the performance of KOFF, often the state of the end-user PC and the Mailbox being synced are more impactful factors.
The Kerio Outlook Connector Offline Edition (KOFF) runs a separate process called KoffBackend.exe. This program performs much of the caching of data from the local email database. On a large mailbox, this process may consume upwards of several hundred megabytes. For this reason, it is recommended for the computer using KOFF to have at least 4 GB of RAM.
KOFF tends to function best when used with an SSD due to continually caching and storing mailbox content. While end-users can use traditional spinning hard drives, consumer-grade HDDs’ slower read and write speeds can result in slower performance.
Conversely, Network Attached Storage(NAS) is not recommended for storing the KOFF cache. By design, KOFF assumes it is stored in a local disk and, based on this, executes local Firebird database queries. If NAS is used, this can result in data corruption and KOFF stability issues.
Mailbox Size and Synchronization Speeds
The speed at which KOFF can synchronize data, especially during the initial sync, is closely tied to the network throughput available. However, perhaps more important than the network speed is the size and organization of the Kerio Connect Mailbox. As the size of the mailbox and user folders increases, there is a direct impact on sync times. It is not unexpected for mailboxes well above the recommended size to see total sync times move from minutes to hours.
For this reason, to ensure a smooth user experience, it is suggested that users strive to keep their mailboxes as close to our recommended mailbox sizes as possible:
- Total Mailbox Size below 20GB.
- Mailbox Folders contain less than 10,000 items.
- Note: This is most important for the top-level folders, such as the Inbox, Sent Items, and Deleted Items. These top-level folders are “opened” or referenced most often, which can also lead to overall server performance.
While the total size impacts synchronization and performance, the folder item count has the most significant impact.
Installing Kerio Outlook Connector
KOC and KOFF are installed using EXE or MSI files available directly from the Kerio Connect mail server. These can be acquired from the main login page of Webmail or the Avatar menu once logged in.
Once acquired, you can Install the Kerio Outlook Connector by running the acquired install package and following the installation wizard. After the installation has been completed, you can either use the Automatic Configuration Tool to install your user profile into Outlook or manually create this from the Outlook Mail Setup panel.
Supported Software Versions
An important consideration when installing the Kerio Outlook Connector is the version of Kerio Connect, Windows, and Outlook that you intend to use. It would be best if you verified that the version of Windows and Outlook are fully supported for use with KOFF. Note that support for standard KOC is limited, and in most cases, KOFF should be used instead.
Not all versions of KOC are compatible with all versions of Kerio Connect. When downloading KOC from your Kerio Connect Server, it will automatically deliver the appropriate version for the connection. This is an essential consideration if you intend to connect to multiple Kerio Connect servers running different software versions, as you may encounter unexpected behavior when the versions are mismatched.
Due to the variance in the release schedule for the various versions of Outlook, it is possible that your supported version of Outlook currently exhibits unexpected behavior following a new update. Often these issues are related to changes in MAPI handling and can be addressed by temporarily rolling back to a stable release of Outlook while awaiting Microsoft’s resolution.
Outlook’s Volume-Licensed (VL) version is commonly impacted by these staggered release cycles due to being a few cycles behind the non-VL versions of Outlook. Issues that Microsoft has already patched on the non-VL versions may reappear within the VL releases as the release cycle catches up, as seen within KOFF installation fails with 1722 error.