How to delete thousands of contact email addresses A year ago when I upgraded my iPhone to the latest model, the computer technician who works on our business computers helped me with a couple of issues with which I was having problems.  He doesn't know what happened, but he ended up importing my complete business address book email addresses into my iPhone and now I have over 4,000 contacts of customers I will never contact with my personal iPhone.

This presents a great problem for me each time I want to look up a personal contact, I have to wade through hundreds of names until I find the one I need.   Is there a program that will allow me to work with this huge contacts list outside of the iPhone (such as on my regular computer with a large screen) and permanently delete those contacts that I don't need?
I'm not sure if this will solve the problem exactly as you specified, but you can hide those 4000 contacts of customers on your iPhone with the steps below.

If your entire email's contacts are synced with your iPhone, you can choose to display only actual contacts and hide those email contacts with the Groups button in the Contacts.app in iPhone



For instance, this is a sample screen that could show when you touch Groups



Also, if you go to your Mail settings on your iPhone (Settings => Mail, Contacts, Calendars) and your Mail account, you can choose to remove your email contacts from your iPhone contacts by turning Contacts off in the picture below.