Corrupt suggested contacts in Outlook

asmartinsen used Ask the Experts™

This is the second time for us we experience corrupt suggested contacts. The problem is that everything seems to work, but when the mail is sent it sends to another suggested contact. A link fails somewhere. If we delete the suggested contacts the problem is gone, but it might happen again and somebody might send an important e-mail to another person.
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What version of outlook are you running

A good tool for looking a little closer at a corrupt autocomplete list is


We use Outlook 2010, Microsoft stopped using nk2 fies after 2007.
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Top Expert 2012

Correct NK2 Files were no longer used after 2007

However, some of the NK2 apps have been updated to work with the stream_autocomplete in 2010

On known to work with 2010 is

Ideally the Autocomplete should be sending to the correct contact

If you enter it should go to

If its going anywhere else, it couls be possible the contact has an autoforward setup.
If they are meeings also possible the recipient may have delegates.

I would also check that Office 201 has the latest SP installed


We deleted suggeste contacts last week. Seemed like the problem was over. Today, it happened again though. So, we deleted the auto-complete list and created a new outlook profile and hope it fixes it.
But what is happening... These are confedential e-mails being sent to random people. For us, we nee to shed some more light on the situation and some users are frustrated right now.
How can we ensure this wont happen again.
Top Expert 2012

To be honest....

My gut feeling is that the problem is not the Auto Complete

You should be able to verify this using NK2Edit
Install it and open the Stream_AutoComplete Dat file
If the autocomplete was corrupt you should see the AutoComplete Display Name and the Email address associated to it.

Im Willing to bet the Recipient who is receving the email has a rule or auto forward setup sending the email to the alternate email address.

Or on the recipients end, the Person who is getting the email
Has the SMTP address in their Email Addresses on their Exchange Account


We're thinking about removing both autocomplete and suggested contacts functionality now.. as it doesn't look like there is no other way to prevent this random corruption of dynamic contacts.
It's a little strange, because ppl have had issues with this every release of Outlook. a conclusion I got after googling simillar incidents and nobody reports a reason for corruption, just a solution in clearing the autocomplete and suggested contacts.
Top Expert 2012

Just a thought here.."Issues with every release"

This would tend to tell me there must be a contributing factor outside of outlook

Assuming the Files and Conenctions are becomming corrupt

Might have a look at AV, Malware, or any product that could possibly be scanning the NK2 or dat files.

Could be a similar situation to having these on an exchange server sanning the they are known to cause performance issues and or corruption
it happened again to us and we have opened a case at Microsoft. Hopefully they can shed some light on this issue.

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