Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows XP and Windows Vista
In Microsoft Office Outlook 2007, a shared folder is unexpectedly cached to the Offline Folder file (.ost). This behavior may occur if you have not opened the shared folder in the past.
In Office Outlook 2007, shared folders (Calendars, Contacts, Tasks) that users access in other mailboxes are downloaded and cached in the user's local .ost file when Cached Exchange Mode is enabled.
Note For example, when you share a calendar folder together with another user, and the user opens it, Office Outlook 2007 starts to cache the calendar folder locally on the other user's Outlook client. The user has offline access to the folder and is not affected by any network issues. However, when you share a shared Mail folder, such as the Inbox folder, with another user, Office Outlook 2007 does not cache the Inbox folder locally on the other user's Outlook client. Therefore, the user who wants to access the Inbox folder may experience delays accessing this folder because of network issues.
Shared folders are generally added to another user's Outlook client in two ways:
The user opens a shared folder without direct access to the mailbox that contains the shared folder. The user can do this by using the File menu (on the File menu, point to Open and then select Other User's Folder), through a sharing message, or through the Open a Shared Calendar link in the Navigation pane.
The shared folder is opened because of the user adding another user's mailbox to their profile. For more information about how to add more mailboxes to an Outlook profile, please see the following article in the Microsoft Knowledge Base.
291626 How to manage multiple Exchange mailbox accounts in Outlook
Regardless of how the shared folder is added, the default behavior in Outlook is to cache the shared folder data locally in the .ost file.
To work around this behavior, use one of the following methods:
Disable the caching of the shared folder in Outlook 2007 on an individual user basis. To do this, follow these steps:
In Outlook 2007, click Account Settings on the Tools menu.
On the Email tab, click to select the Exchange account, and then click Change.
Click More Settings.
On the Advanced tab, click to clear the Download Shared Folders (excludes mail folders) check box, and then click OK.
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
Set a registry key to disable the caching of the shared folders for any new Outlook profiles that are created. To do this, follow these steps:
Click Start, click Run, type regedit, and then click OK.
Locate and then right-click the following registry subkey:
Right-click Cached Mode, point to New, and then click DWORD Value.
Type DownloadSharedFolders, and then press ENTER.
Right-click DownloadSharedFolders, and then click Modify.
In the Value data box, type 0, and then click OK.
To change this setting for your existing profiles, use the steps that are outlined in Method 1.
This behavior is by design.
You can configure the settings of cached shared folders by using the Office Customization Tool (OCT) when you customize your Cached Exchange Mode deployment. For example, you may want to disable the settings if the users in your organization open many shared calendars and if the users work together on the network that uses reliable links to access Exchange servers.
When you open a shared calendar for the first time, the shared calendar folder is added to a list of folders that are synchronized to the .ost file. If you are a delegate and you accept a meeting request for the first time as a manager, the folder that contains the calendar for the meeting request will be added to the list. If you directly book a meeting in another user's calendar, the folder that contains the calendar for the booked meeting will be added to the list. In this manner, you can unexpectedly trigger the process that adds a folder to the list.
In order to remove the folder from the list of shared folders, you must manually click to clear the Download Shared Folders (excludes mail folders) check box when you change the account settings for the Exchange account.
The shared folders are automatically aged out of the list when the shared folders are not synchronized for some time. For example, this can occur if you no longer have permission to access the shared folders. The shared folders can also be aged out of the list when you do not locate or view the shared folders for some time. For example, you set the value of the SharedFolderAgeOutDays registry entry to 45. When User A opens the calendar of User B in Outlook, and then does not view it again for 45 days. At that point, Outlook stops synchronizing the data with Exchange, and the calendar is not updated. If after this time User A opens the User B calendar, it is synchronized and the age out countdown timer is reset to 0 days.
When you have set the values of the following registry entries, you may experience the scenario that is mentioned in Symptoms section.