Outlook contact updating
If you have a Gmail email account (I guess most people do these days), you can use it to merge duplicate Outlook contacts. Export your Outlook contacts to a file, import that file to your Gmail account, use "Find and merge duplicates" function available in Gmail, and finally import the deduped contacts back to Outlook.
If you want more detailed instruction, here you go: Of course, the Link Contacts feature is not the best choice to clean up a large contacts list cluttered with duplicates, but it will definitely help you quickly merge a few identical contacts into a single one.
Now that you've cleaned up the mess in Outlook contacts, it makes sense to invest a few more minutes and lean how to keep your contact list clean in the future.
This can be easily achieved by enabling the automatic Outlook duplicate contact detector.
To better understand what I'm talking about, see how the data in the original file looks like: And here is what we have after using the Combine Rows Wizard.
If you are interested to try the Combine Rows Wizard on your own data, you can download a fully-functional trial version here.
using his or her corporate email address and a personal Gmail address.
However, if you also create contacts manually once in a while, you may end up having multiple contacts for the same person, e.g.
if you misspell the contact's name or enter it in a different way.
And below you will find a number of solutions to choose from.
In most cases Outlook is smart enough to prevent duplication when you are trying to create a contact that already exists.
In this case, no matter how you create a new contact, by dragging a message to the Contacts folder or by clicking the "New Contact" button on the ribbon, an additional contact for the same person will be created anyway.