Sue,
I have found that adding in the Profile name (ProfileName=Outlook) as per
below has eliminated this issue. Thought you would like to know this.

;Automatically generated PRF file from the Microsoft Office Customization
and Installation Wizard

; ************************************************** ************
; Section 1 - Profile Defaults
; ************************************************** ************

[General]
Custom=1
ProfileName=Outlook
BackupProfile=No
DefaultProfile=Yes
OverwriteProfile=Append
ModifyDefaultProfileIfPresent=TRUE

; ************************************************** ************
; Section 2 - Services in Profile
; ************************************************** ************