Cannot delete files

I moved files from my computer that i downloaded to my flash drive, but now I want to delete them, when I try it shows me this

these are my diagnostics if you want them eos-diagnostic-180908_134841_UTC 0300.txt (164.7 KB)

@vangel023 Have you tried formatting the pendrive?

how can i format the pendrive

sorry i found how i can do it

Click the right mouse button

I fotmat it but now i cant find it in the documents

When the formatting is finished the pendrive will appear again