Help Duplicated every contact entry. How to delete?

[Pi]

Droid 1 (2009), running android 2.2.3

I tried to back up my contacts to Outlook using 'my phone explorer'.

somehow it duplicated every entry on my phone.

How to fix?
or is the only easy option to erase everything by resetting phone and restore from Outlook? plus reinstall apps?

thx!

 

[Pi]

downloaded app called 'duplicate contacts.'

it found and deleted all the dupes.