expand shows full but have deleted files

Hiya

My iXpand show’s it is at full capacity. When I plug it into my Macbook or iphone there are no files on it to view. I’ve tried reformatting it using Disk Utility but it keeps saying “Couldn’t open device.” Any thoughts please?

Thanks!

if you deleted files from a mac and did not empty the trash you will need to format the drive to recover the space. See the knowledge base article below from the sandisk support site. If you have high sierra make sure and follow the steps for high sierra as they are a little different. 

https://kb.sandisk.com/app/answers/detail/a_id/203 

Thanks for replying. Do you have another link? That one just says “Permission denied”

thats strange. try this one. 

https://kb.sandisk.com/app/answers/detail/a_id/203

if that does not work go to the link below and type 203 in the search bar and it should come up

https://kb.sandisk.com/