What filesystem are you using and how did you format it?. ext filesystems need permissions to read and write. Try to right click the drive window where you see copy and paste and select "Open as administrator" enter your password and then you should be able to copy/move/delete files.
If you can access the drive with root account in thunar right click it again and select "Properties..." and allow write and read permissions from "Permissions" tab. Now it should work until you format it again.
Linux lite series 4 is based on ubuntu 18.04LTS. Series 4 means every version of linux lite 4.x. Linux lite 4.4 is based on ubuntu 18.04LTS because it's one version of series 4
If you can access the drive with root account in thunar right click it again and select "Properties..." and allow write and read permissions from "Permissions" tab. Now it should work until you format it again.
Linux lite series 4 is based on ubuntu 18.04LTS. Series 4 means every version of linux lite 4.x. Linux lite 4.4 is based on ubuntu 18.04LTS because it's one version of series 4