gSyncIT is a third party synchronisation application. This works really well as a utility to synchronise Google Contacts <> Outlook.
gSyncIT has broad compatibility with different versions of Outlook and is well supported, documented and updated.
The gSyncIT website is HERE.
gSyncIT has many options available to customise the behaviour of your sync from Google to Outlook. There are some general tips that might help setup and troubleshoot any duplicates that might be created.
1. We advise that you should set your gSyncIT contacts sync settings to use the Google Gmail contacts as your Primary List
2. There are certain settings, for example changing how gSyncIT manages Deleting Contacts, that change the field mapping in gSyncIT - this will result in a complete re-sync of all the contacts, this can (in some cases) create duplicates.
If you have your Primary Contact List set to Google (as advised above) your duplicates are created in Outlook but do not generally affect your Google Gmail Contacts list.
If you have the Primary List set to Outlook Contacts then the duplicates are most likely going to update your Gmail Contacts list and created duplicates here also - this has the knock on effect of creating duplicates in OpenCRM.
Important : whenever you make a change to any settings in gSyncIT and you are warned that that the action will "reset your field mappings" you should take care. This is the most common cause of duplicates being created and therefore, duplicates being pushed through the synchronisation chain, back into Google and ultimately OpenCRM.