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Duplicate Contacts in Outlook (39,000 of them)

Posted on 2012-09-05
Medium Priority
Last Modified: 2013-03-15
We have a client who is experiencing duplication of their Outlook contacts.

One user needs his contacts accessible on his iPhone and iPad, as well as Outlook and other staff use the same contact list.

The size of the contact list is 4,305. Recently it blew out to 39,000. I was able to remove the duplicate entries using a 3rd party Outlookfreeware.com tool.

What I would like to know is how to ascertain the cause of the duplication of emails.
I suspect it could be due to sync of multiple inboxes and devices with the one contact list.
Question by:ITtelligent

Expert Comment

by:Glenn M
ID: 38369852
Check to see if it is outlook addons creating the problem. Additionally see if sync contacts is enabled on the Ipad device.

Is outlook in cache or online mode? I suggest online mode for now.
Use Outlook in Savemode and then attempt to sync and see if the issue reoccurs.
LVL 52

Expert Comment

by:Manpreet SIngh Khatra
ID: 38370061
What I would like to know is how to ascertain the cause of the duplication of emails - Sorry there isnt a way or logs that will tell how the duplication happened (Its mostly the Handheld device issues when upgrading or sync with multiple accounts).

There is another good tool to remove Duplicates OVID.

- Rancy
LVL 47

Expert Comment

ID: 38370322
Duplicate Contacts in Outlook is 99% of the time related to the sync of a mobile device to exchange

Theres a few way this can happen

usually the default setup on Mobiel Devices with Active Syn are set for Two way Sync
Once the phone is synced initally, the contacts are copied over
Next time the phone Syncs, its syncing back those contacts to exchange for the user
Each time the sync occures the contacts are duplicated

Another way this happens is

The user may have already previously had contacts on their phone that are the same in their Outlook Contacts

When the phone syncs these, contacts are added to the users contacts in Outlook/exchange

Once you have removed all the duplicates in outlook

You can change the SYNC to one-way to phone only
This will stop the duplicates from happening

Otherwise, if the user requires the two way sync

When deleing duplicates in outlook
Make sure they are exactly the same

After the phone sync
Some may just have phone numbers
and some may be the email contacts

Make sure there are no "Duplicates" with spelling mistakes or variations in Format such as
Jon Doe
Doe, Jon

Conacts like this will get duplicated every time

ONce you happey that outlook has all the users Outloook contacts, and all the mobile contacts that were synced from the phone...

Go back to the mobile device
Remove the exchange sync
Clear the inbox, calendar, contacts ect ect

Now re-setup the two way sync

This will sync all the contacts from outlook back to the users phone

User should have all the contatcs they had and the outlook contacts

Just make sure the user is aware when updating contacts to check for existing contacts first
If they exist edit the contacts in the phone, dont create a new one

If they do not exist, enter it in the phone how they would in outlook

Same goes for Outlook
Make sure they odont add contacts in Outlook that may already exist on the phone in a different format as above

Accepted Solution

ITtelligent earned 0 total points
ID: 38371073
We've narrowed it down.

We turned on Mailbox Access Auditing and narrowed the culprit down to an iPhone. Noting high resource use by w3wp.exe too, we've narrowed this down to a known issue with some devices syncing large numbers of contacts.
It seems there's no real fix as yet. We're culling some contacts and pinning our hopes on iOS 6.

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