Had an issue where the time matters sync was creating duplicate contacts and events.
In my experience this was caused by:
Moving the TM database
but most directly to the way the exchange sync works: syncing from a phone can remove fields which TM determines to be new events/contacts, so it places them as such.
Solution 1: Stop the sync going from exchange back to TM:
This means that events modified in TM would be modified on exchange, but not the other way.
This leads to the problem of removing an event from outlook/phone and having it replaced by TM as it realizes it's missing from exchange.
The caveat here being, only make deletions and edits from TM.
This was unacceptible, so we left the sync as is. As the dups didn't seem to be occuring with great frequency after our changes to their network. And this was preferable to the hastle of changing the way the business operated.
So, in that mode of thought.
Solution 2: How to remove duplicates:
From TM go to File > Utilities > Remove Duplicate Contacts.
LN Support Instructions
View All Events > right click on an empty space in the sorting bar > choose columns > find and select "created date", hit OK > sort by creation date.
All duplicate calendar events will be created on the same day. Right click on them individually, tag, and then once you've gotten everything tagged, delete tagged events.
Do not filter by a date range, select all and delete. If you do this, there is a recycle bin you will have to pull all your events from.