Norton is constantly scanning my external hard drive

I have an external hard drive hooked up to my pc that I use for the backups. The problem is that Norton keeps running scans on the drive. As soon as it’s done and says everything is fine I press the finish button and two minutes later it starts the scan again. It keeps the damn computer from going into sleep mode while the “alls clear” message stays up. I need the external drive because I have more than the cloud will take. What do I need to do?