Are you saying that data you have put on the Seagate appears to be missing? If so you could try Recuva
By the way, looking at your profile you have never "green ticked" a question you have posed - I hope they are not still unresolved.
OnePlus 6T McLaren edition costs more and charges faster
Amy Cesal's Play-Doh infographics bring fun and colour to datavis
New Apple Products 2019: Predicting the new Apple products coming soon
Modifier un PDF : les meilleurs éditeurs PDF