For Duplicates on the Pre, it sounds like the system is working as intended.
You synchronize Outlook through Google, which made a Google set of Calendar items on your Pre.
Then you synchronized Outlook through another tool, and it made a set of Calendar items on the Pre that are tied to that tool.
So on the Pre, you can select to look at one set or the other set. The default setting shows you both sets, so it looks like duplicates even though both sync products and the Pre are all working as intended.
The solution here is to delete one set from your Pre, which you can do by removing the account. Or just change yoru view to show only one account.
If the duplicates are in Outlook, which can happen because you are using different sync products which may conflict, there is an easy way to remove them.
In Outlook select View, Arrange By, Current View, by Category.
This gives you your calendar in column mode. Right click on the column names, and add the column "Created". This is the create date for the record.
Click on column header of "Created" to sort in date/time order. This puts all your dupes together, since they were created by a sync process within a few minutes. Save these to a safe spot (copy and paste) in case you want them back later, and then delete them.
Then reset your View back your normal setting, and your Outlook Calendar should be all cleaned up.
If you used CompanionLink, and this problem happened, give our tech support a call and they can walk you through the steps to clean up. CompanionLink tech support is free.
Wayland Bruns, CEO/CTO
CompanionLink Software, Inc.