PRB: CDO (1.x) Error: Run-time error '-2147221233' with GetFreeBusy()

Using the GetFreeBusy function against a Exchange Server mailbox returns the following error:

The mailbox that you are accessing using Collaboration Data Objects (1.1, 1.2, 1.21) has not been logged into with a mail client yet, therefore no Free/Busy information has been created for this mailbox.

Here are three workarounds to this problem:

1. Log into the mailbox with an Outlook client to ensure that there is some Free/Busy information written to the mailbox. When you log into mail for the first time, Outlook creates an appointment item which in turn creates Free/Busy information.
2. Log into the mailbox with an Exchange client and start Schedule+ or just start Schedule+ by itself. This creates Free/Busy information in that mailbox, there is no need to actually create an appointment.
3. Use CDO (1.1, 1.2, 1.21) to create a new test appointment so that Free/Busy information is created for that mailbox.

The GetFreeBusy method returns a string representing the availability of the messaging user for a meeting over a specified period of time. The returned string length equals the number of time slots between StartTime and EndTime. Each character in the string is the ASCII representation of the appropriate type library constant indicating the messaging user's availability during a time slot: