I/O error and missing files

my passport shows an I/O error when i try to transfer data from my desktop. and it shows thats its empty but it says 322 gigs available. it has 500. is all of that data lost?

Data is corrupted. Try to fix the partition with  CHKDSK or  Test Disk.

There’s you might be able to fix it, However you will need a Data Recovery software to get the files if it does not work.

Try  Mini Tool Data Recovery