I have a 4TB Hitachi HDD that I purchased in Europe (I use it as a backup disk); I use Windows 7. When I connect it to a SATA port, it is recognized in Windows Explorer and gives no problems, even after transferring 3TB at a time or after being on for days.
When I connect it via a SATA-to-USB2.0 adapter, it is also recognized, but when I transfer a large amount of data, it will intermittently stop being recognized by Windows Explorer and cancel the transfer.
When I connect it via an external enclosure (which is technically a SATA-to-USB3.0 adapter), it does not display at all in Windows Explorer, but Disk Management will show the drive, albeit uninitialized (prompts for format).
I only got the external enclosure because I want to backup my files more conveniently (instead of having to open the computer case each time).
Do you advise against reformat/initialization via the external enclosure? Can it screw up things in an irrevocable way (Master Boot Record etc.)?