What's going on with this update??

So I'm trying to download the USSEP after the new update and I'm getting this message pop up? "Lacking permissions to write folder of download. Operation cancelled." Does anyone know how to fix this??

So I'm trying to download the USSEP after the new update and I'm getting this message pop up? "Lacking permissions to write folder of download. Operation cancelled." Does anyone know how to fix this??