Understanding the Advantages of Outlook Cached Mode Configurations

Many of us have heard about or actually used the Cached Mode of the Microsoft Outlook application. By specifying various configurations, we can make the best use of this powerful feature. Our article explains the different configurations and how to put them to use.

As all users of Microsoft Exchange Server are aware, they can either work with their mailbox on the server in the online mode or the cached mode. The biggest advantage of working in the cached mode is that it allows users to continue working with data from the mailbox as though they were still connected to the server even though they may be offline. Outlook creates an offline storage file, OST file and then copies the content of the mailbox on the server into this file. Mobile users can then access this copy of the mailbox offline. To take full advantage of this feature, users should know about the different configurations of the Cached mode setting, how to protect OST data and if the need arises, how to recover OST data.

Though you can set the various configurations for Outlook manually, if you are a system administrator looking after an entire Exchange organization, you would be better off if you just applied the settings at the group policy level. The OST group policy settings can be located by first going to the main User Configuration menu and then looking at the Administrative Templates. From Microsoft Office Outlook 2007, select Tools and then Account Settings, from where you can click on Exchange. While there may be other options, you should look at the group policy setting for the OST files. Before making changes, you should be aware that some of the changes could cause serious damage to OST files and that there should be a backup option to quickly recover OST data.

1.Rather than downloading all the messages to the offline folders, especially if you are working on a low bandwidth connection, you might want to download only the headers to understand what you need to deal with on a priority basis. If you indicate the ‘Cached Exchange low-bandwidth threshold value’, when sufficient bandwidth is not available, Outlook will download only the headers for you.

2.One of the most important configurations is the ‘Exchange Unicode Mode’. While older versions of Outlook used only the ANSI format for their OST files, from Office 2003 onwards, it is possible to choose the format the user would like for the OST files. However, users should be aware that ANSI-based files have a 2 GB size limit beyond which the files can immediately get corrupted and you have to repair the file to recover OST data. Further, it is not always easy to work on an OST file that has crossed the size limit, as, in order to repair the file, one needs to reduce the size. The best option then is to use specialized recovery tools such as Advanced Exchange Recovery from DataNumen to repair the OST file, bring the file to a more manageable level and ensure no loss of data. On the other hand, Unicode files have no such restrictions.

3.Some users prefer to work with the data in their Exchange mailbox only when they are online. They would much rather deal with slow and unreliable connections than deal with local OST files. By choosing the ‘Do not allow an.OST file to be created’, these users do lose out on the many advantages of the Cached Exchange Mode.

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