The following steps will provide the ability to mask/filter UM messages in your Inbox and create an additional view that shows only UM messages. Since the messages will still be in the Inbox, all other UM functionality (message light, using phone to pick up messages) will still exist. It is important to note that these changes will not have any positive impact on the your folder size.
Altering your message view to filter out UM Messages:
Start Outlook
Click on "Inbox"
Click "View" on the toolbar
Click on "Current View"
Click on "Customize Current View". This will bring up the View Summary Box.
Click on "Filter"
Click on the "Advanced" tab
Click on the "Field" dropdown
Click on the "All Mail Fields" selection
Click on "Message Class". This will place "Message Class" in the field filter.
Change the condition to "doesn't contain"
In the value field, type "IPM.Note.Voice.Unity" (without the quote marks)
Click "Add to list"
Click "OK"
Click "OK"
Adding an additional view to only see UM Messages
Start Outlook
Click on "Inbox"
Click "View" on the toolbar
Click on "Current View"
Click on "Define Views"
Click "Copy"
Change name of new view to "Voice Mail Only"
Click "OK"
Click on "Filter"
Click on the "Advanced" tab
If you have already changed the message view to filter UM messages, perform the following steps. If not, see below.
Click "Remove"
Change the condition to "contains"
Click "Add to list"
Click "OK"
Click "OK"
If you have not already changed the message view to filter UM messages, perform the following steps.
Click on the "Field" dropdown
Click on the "All Mail Fields" selection
Click on "Message Class". This will place "Message Class" in the field filter.
Ensure the condition is set to "contains"
In the value field, type "IPM.Note.Voice.Unity" (without the quote marks)
Click "Add to list"
Click "OK"
Click "OK"