Q. I have exported contacts out of my account and I have added industry types. But I have deleted some cells with information would this matter? Will the information still be there when I import and will they overwrite?

A: As long as you make sure you keep the ICUniqueId column and only change the data in the cells when you then re-import the data back in you will not get any duplicate records and any changes made to the Excel spreadsheet will overwrite existing info in your account. 

Important Note:

The ICUniqueId  column must be in the spreadsheet when you re-import after making changes otherwise it will not know which contact record to update the new changes with.