Outlook to iPhone sync failure – Sync suddenly stopped working for calendar events but continued for contacts and notes. Finally Fixed!!! SUPPORT TEAM – PLEASE SEE THIS – Complete explanation of cause and correction steps.

Question

The issue:  Outlook to iPhone sync failure – Sync suddenly stopped working for calendar events but continued for contacts and notes.   Finally Fixed!!! 
SUPPORT TEAM – PLEASE SEE THIS – Complete explanation of cause and correction steps.
The cause:  It is now clear what caused this problem.  For years I had several “all-day” events in my Outlook calendar (birthdays, anniversaries, etc.).  In May 2012 I decided to make some of them one hour  events so I could add alerts to remind me of the event.  I did this by dragging them in Outlook to the time I wanted and expanding them to the time slot desired and then adding the alarm.
The symptom:  Syncing stopped working for the calendar but continued working for contacts and notes.  I didn’t realize sync was failing until months later when I missed two very important phone calls, so when I noticed it the cause was not obvious. 
The failed attempts:  I’m head of a software firm and my calendar sync is a crucial to my business life so I took this on with a vengeance.  From a quick look at events in Outlook and the iPhone I could see that the problem started in May 2012.  Events before May were in both Outlook and the iPhone but events after May were only one or the other.  Unfortunately I had changed several other things at the same time relating to other events so again the cause was not obvious.  MANY calls with AppleCare proved them incompetent so my internal IT guys assisted trying many things.  We tried a huge number of calendar changes and several versions of iTunes, iPhone OS and Office as well as both iPhone 4 and 5, all without success.
The fix:  After 18 months of frustration, MANY  hundreds of $ expense and MANY hours of wasted time I saw a blog that had a calendar sync  problem and it indicated all day events were related.  I changed the display of the Outlook calendar to the list view, added columns so I could see “all day” event check marks as well as times of events,  sorted on the “all day” event column to move them to the top, and for all events that were “all day” events AND had a start and end time, I removed recurrence and then added the annual recurrence back…
After I fixed all events that had BOTH “all day” set and had a start/end time, I tried another sync.  It synced for the first time in 18 months! 
Problem occurred May 2012 – fixed Nov 2013

Answer 1

Hi, to remove dummy '_ModGrp' entries, rather than crashing the 'Suppr' key on your keyboard, you can use this basic VBA macro (launched for instance from Excel).
It will recursively remove all '_ModGrp...' folders
Sub RemoveFolders_Click()
    Dim oOutlook As Outlook.Application
    Set oOutlook = New Outlook.Application
    Set objNameSpace = oOutlook.GetNamespace("MAPI")
    Call CleanFolders(objNameSpace.Folders)
End Sub
Sub CleanFolders(objFolders As Outlook.Folders)
    For i = objFolders.Count To 1 Step -1
        If Left(objFolders(i).Name, 7) = "_ModGrp" Then
            objFolders.Remove( i )
        Else
            If Not objFolders(i).Folders Is Nothing Then
                Call CleanFolders(objFolders(i).Folders)
            End If
        End If
    Next i
End Sub