I’ve been granted access to several large mailboxes and Public Folders which I’ve marked as Favorite. As I’m also regularly off-line, I’ve configured Outlook to also cache this shared content. However, the result is that I now have a really big ost-file.
I was hoping that with the Sync Slider feature in Outlook 2013, I was able to limit how much was being cached and reduce the size of the ost-file. I’ve set the Sync Slider now to 30 days and it seems to work on my own mailbox but it doesn’t have the same effect on my shared mailboxes and Public Folders.
Does the sync slider affect these shared folders at all? If not, what alternatives do I have to reduce the total size of my ost-file?
No, unfortunately, in Outlook 2013 the Sync Slider doesn’t apply to the caching of shared content. It only applies to your own mailbox, or to be more precise: the primary mailbox which is associated to the Exchange account.
However, in Outlook 2016, the Sync Slider feature has been updated and also applies to shared content.
When you are still using Outlook 2013, and depending on your access rights, you can either configure the additional mailboxes as additional Exchange accounts or apply Synchronization filters.
The Sync Slider can be found in: File-> Account Settings-> Account Settings…-> tab E-mail-> double click on your Exchange Account.
Full Access permissions for additional mailboxes
If you have been granted Full Access permissions to these mailboxes, you can also configure them as separate Exchange accounts. This will create an additional ost-file for each account for which you can configure the Sync Slider.
You can verify with your Exchange administrator if you have indeed been granted Full Access permissions to the mailbox. The owner of the mailbox can’t grant you these permissions him-/herself via Outlook.
No Full Access permissions to mailbox and Public Folders
If you haven’t been granted Full Access permissions for the additional mailbox or in the case of Public Folders, you could set additional Sync Filters to reduce the amount of data that is being cached.
You can access the Synchronization settings for a folder by right clicking on it, choosing Properties and then selecting the tab: Synchronization.
For more details about using Synchronization Filters see: Reduce ost file size with Synchronization Filters
Affected folders by the Sync Slider
Aside from not affecting secondary mailboxes added to your Exchange account and Public Folders, the Sync Slider also doesn’t apply to the following folder types:
- Shared or delegated
Note 1: I’ve submitted a feature request to the Outlook Team to have the Sync Slider also apply to the cached mail folders of delegate mailboxes as they often are as large or even larger than your own mailbox. As mentioned before, this feature request got implemented in Outlook 2016.
Note 2: For more background information about the Sync Slider feature see: Only a subset of your Exchange mailbox items are synchronized in Outlook 2013