Recently I ran into a similar issue with three separate users who had installed the Outlook Client for CRM 2011. Since the out of the box outlook client downloads all contacts owned by the user, they ended up with hundreds, or even thousands in some cases, of CRM contacts mixed in with their existing outlook contacts. As a mobile sales staff, having all these contacts on their mobile devices was not desired. Not knowing the right way to manage their data groups they had simply disconnected CRM, or in some cases uninstalled the entire outlook client. What this left behind was all the CRM contacts mixed in with their pre-existing contacts, and no obvious way to tell them apart. Ultimately, they needed a way to clean up their outlook contacts; this is the solution I took to make it happen.
First, open outlook and go to Contacts > View > Change View > List
Switch to List view
Next Right Click on the column headers and select Field Chooser
What you want to do next is add a field that you can filter on, this will allow you to tell the difference between your outlook contacts and CRM contacts. All your CRM contacts have a user defined field called crmid, so you will add that field:
First Click New --> and type in crmid in the name box
Next you need to add the field to your list of contacts. To do this, change the filter to User-defined fields in folder
Next select the new field we added crmid and drag it into the list.
Now you have a list of all your contacts, as well as a new column that shows you which ones are CRM contacts. The last step is to filter out all of your outlook contacts so you can delete / deactivate / move / whatever, all the CRM contacts.
To do this right click on the column title bar again and select View settings
Click ok, the list only shows the contacts that were downloaded from CRM. You can now safely select all and delete or take whatever action you want without risking loss to your existing outlook contacts.
Finally, go back into the View Settings and turn off the filters.