Where CDO Publishes Free Busy Information

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From time to time, I get asked to explain where CDO publishes Free Busy information in the Public Folder store, so I figured I’d put this article together. The basic process CDO uses for updating FB information is outlined in the More Information section of KB 278954. We’re concerned with the part of the process summarized as “queued up to be sent to the site’s Free/Busy public folder.”

The first thing CDO does is to open the Public Folder store and read a couple properties off of it, PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID (0x66250102) and  PR_SPLUS_FREE_BUSY_ENTRYID (0x66220102). These entry IDs will point at a couple folders in the Public Folder store. The first entry ID points the Free Busy folder for the user’s site, the folder CDO wants to look in for the Free Busy message. If CDO cannot open the folder specified by PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID, it turns to the second property, PR_SPLUS_FREE_BUSY_ENTRYID, which points at the “SCHEDULE+ FREE BUSY” folder, a child folder of the NON_IPM_SUBTREE folder. This property will point at the same folder for all users. In this case, CDO will use an algorithm similar to the one described in [MS-OXOPFFB] to find the correct site folder for the Free Busy message.

The point of failure here is the Entry ID specified in PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID. If this points at the wrong folder, CDO will publish Free Busy information to the wrong folder, and other clients won’t see the updated Free Busy. This property is not one that anybody sets. It’s actually computed on the server side. No amount of changes to a CDO based program can get it to publish Free Busy to the correct folder if the server is handing out the wrong site folder.

This is where server side troubleshooing articles such as KB 326637 and Exchange Public Folder Troubleshooting Resources come in handy. They walk you through the various things that could be wrong with site folders and how to fix them. If PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID is pointing at the wrong folder for your users you’ll need to use the steps in those articles to locate the problem and fix it.

Suppose you just want to determine if PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID is pointing at the folder you’d expect it to point to for a particular user. You can use MFCMAPI to see where this entry ID points to.

First, we check which folders we’re being pointed at:

  1. Open MFCMAPI on the machine where your CDO application runs.
  2. Log on to a profile. You’ll get your best results if you can use the same profile the CDO application uses.
  3. Select the Public Folder store in the list of stores.
  4. The properties we want may or may not show in the default list of properties, so we’ll add them:
    1. Click Property Pane/Modify Extra Properties
    2. Click Add
    3. In the Property Tag field, type in PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID. The rest of the form should fill out automatically.
    4. Click OK, then click Add again.
    5. In the Property Tag field, type in PR_SPLUS_FREE_BUSY_ENTRYID. The rest of the form should fill out automatically.
    6. Click OK, then click OK again to close the Extra Properties window.
  5. We’ve added the properties, so they should show in the property pane. You can sort by the Property Name column and look them up by name, or sort by the Tag column and look them up by number (0x66250102 for PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID and 0x66220102 for PR_SPLUS_FREE_BUSY_ENTRYID.
  6. Right click on PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID and select Open as Entry ID or Object. In the dialog that comes up, hit OK.
  7. In the resulting hierarchy view, you can now read the name of the site folder the server has directed you to.
  8. Switch back to the main window and reselect the Public Folder store to refresh the property list.
  9. Right click on PR_SPLUS_FREE_BUSY_ENTRYID and select Open as Entry ID or Object. In the dialog that comes up, hit OK.
  10. This will display the hierarchy for the SCHEDULE+ FREE BUSY folder. Click the + icon to display the list of all the site folders in the Public Folder store.

Next, we determine which folders we should be looking at, following the algorithm from [MS-OXOPFFB]:

  1. In the main window of MFCMAPI, select Session/Display Current User Properties. Hit OK.
  2. In the Property Pane, locate PR_SEARCH_KEY (0x300B0102).
  3. Double-click on the property to open it, and take note of the Text field. For me, this says “EX:/O=MICROSOFT/OU=NORTHAMERICA/CN=RECIPIENTS/CN=420275”
  4. The appropriate site folder can be derived by truncating this string at the / before the first CN. So for me, my site folder should be “EX:/O=MICROSOFT/OU=NORTHAMERICA”.

So, now you know what site folder the user has listed in PR_FREE_BUSY_FOR_LOCAL_SITE_ENTRYID, and you know the name of the site folder they should be using. If these two are not the same folder, then you have site folder issues and need to get them addressed.

Hopefully, this should be enough to help folks who are having site folder issues to understand that CDO is just the innocent victim here when it publishes Free Busy to the wrong folder, and that server side configuration is the real villain.

Enjoy!