I successfully installed an existing HDD in an external enclosure, and, using an USB connection, had no problems with my Windows XP Home SP2 OS recognizing it. That was in April. I haven’t used the external HDD since except for today and now I am unable to access it. I get a message saying that it needs to be formatted. However, I can go into Command Prompt and request the NTFS formatting only to get the message that says the HDD is already formatted as NTFS. The external HDD shows up as Drive (F under My Computer and under Disk Management; however, there is no File System showing for the HDD under Disk Management, otherwise it shows as “Healthy (Active)” and “100% Free.” The external HDD appears to be running OK with an alternating blue and red flashing light at start-up, but I can’t access the files. I did an update on the driver (the system said it wasn’t needed), then did an uninstall on the driver and a reboot with no problem of the driver reinstalling itself. Bottom line is that my computer recognizes the external HDD but does not recognize that it is already formatted. How can I get to my files on the external HDD? Thanks ahead of time for your help!

Try using partition table doctor to tray and recover the partition