Even I too had this problem of late/failed detection of my Seagate 1 TB HDD on my LG TV webOS 2.0.
HDD works fine when connected to my laptop(NTFS format) . I checked my HDD content and found that there were some files created with name "ntfschk....." on root folder of HDD(i dont remember creating them). I deleted them and connected back to TV and it is working smoothly.
Hope this helps some of you.