Accessing Public Folders while offline

When I'm offline, I can still read my email thanks to Cached Exchange Mode. However, I don't have access to my Public Folders anymore.

Is there some way I can cache these as well?

Yes, that is possible, but caching a Public Folder is a 2 step process.

Step 1: Enable caching for Public Folder Favorites

  1. Right click on the root of your mailbox and choose Properties.
  2. Click the Advanced... button.
  3. Click the Advanced tab.
  4. Enable "Download Public Folder Favorites".
  5. Confirm the notification, close all open Outlook dialogs and restart Outlook as instructed.

Enabling caching for Public Folder Favorites.
Enabling caching for Public Folder Favorites.

Step 2: Add the Public Folder to your Favorites

  1. Browse to the Public Folder you want to cache.
  2. Right click on the Public Folder and choose Add to Favorites...
  3. Optionally you can click on the Options>> button to configure how subfolders should be handled.
  4. Press OK.

Only Public Folder Favorites can be cached.
Only Public Folder Favorites can be cached.


Be careful of which and how many Public Folders you want to cache as Public Folders can sometimes be very large. You'll download all this data in an ost-file on your hard disk and a really large ost-file could result in poor performance or even connection loss.

Microsoft has set the supported maximum amount of Public Folders that you can cache to 1000 folders or 1GB (whichever is reached first). This is not a hard set limit but I can personally confirm that this is an issue when going well beyond those limits (in fact, the KB article got published thanks to yours truly after months of troubleshooting with Microsoft).

Public Folder - Cannot display the folder. There is not enough free memory to run this program. Quit one or more programs, and then try again.
Be carefull not to cache too much or Outlook may suddenly disconnect on you.

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