In some cases, when you upload leads, you would like to upload the statuses that were saved with the leads. This feature will make sure to have the same status as before instead of setting all leads as a "New Lead" status when you upload.
From the Dashboard, click on Account and select Global Settings from the drop down.
Scroll down and look for Allow Upload Status / User. Put a check in the check box
Click on Apply Changes
Now when you, try to upload leads, make sure you have a Status Column on your list and match that column to the Status Field.