So you cannot ever load the radio memories into a tab, and then import from that tab (i.e. without creating a "New" tab in the menu) with the intention to over write Locations that are listed in the import file?

Exporting To A Generic File

If you wish to save memories from an existing radio out to a generic file that can be imported into other radios or edited by hand, use the Export function in the menu.

1. Start CHIRP and download a temporary image of your source radio
2. Use the Export function to choose a CSV or .chirp file of your radio's contents
3. Choose some or all of the memories to export

Importing From Another File

If you have an image from another radio (even another type), you can import that into an image or live mode radio using the Import function in the menu.

1. Start CHIRP and download a temporary image of your target radio
2. Use the Import function to choose a source file (CSV, CHIRP, .img, or .icf)
3. Choose some or all of the memories to import
4. Upload the changed image back to your target radio

This is the normal way!