In my experience, this means one of the tactile micro switches behind one of the other buttons has shorted (switch is stuck closed). On mine it was the switch for SOURCE/OFF. Unfortunately I think the switch is too small for my soldering skills...

Tamas, Sorry to hear it didn't work well for you. I don't see an obvious answer, but a few things to try: (1) I don't think it's important to pre-format the disk HFS+ (mine just happened to be that, by coincidence). I think the LaCie does not care what format the disk is because it re-formats anyway with its own proprietary (encrypted) format. At least that's my best guess. So you could try a different format like NTFS or whatever, before inserting the disk into the case. (2) I assume you had already enrolled some fingerprints into the drive before you swapped the disks. I think that's why mine worked so smoothly. It just remembered my fingerprints despite swapping out the disk. It might be worth swapping the disks back and confirming that your fingerprints are properly enrolled (using the LaCie software). (3) I'm not sure if it has anything to do with the disk swap, my partitioning, or just the enclosure aging a bit, but I have had a lot of trouble recently getting the drive to mount. The behavior is...

You're welcome Tamas. I can confirm it accepted a 2TB drive (originally came with 1TB). I was also able to partition it into 2 partitions (using OS X Disk Utility), although I did notice that the manual warns against doing this. It seems to be working for now (and much faster than with the original drive), so we'll see how it goes.

Well I finally had time to try the LaCie Rugged Safe upgrade, and I can say for sure that it *is* possible to change/upgrade the drive in this enclosure. It was actually surprisingly straightforward: I removed the rubber bumper, opened the case (latches--should be pretty obvious how to pry them open once you see them), then unplugged and replaced the drive inside. It's a totally standard 2.5" drive; it appears that all the authentication/fingerprint recognition stuff (and even the fingerprint storage) is handled in firmware--none of that seems to reside on the actual drive. The case appears to even accommodate pretty thick drives (the 1TB Toshiba in mine was almost 12mm high). I placed an HFS+ formatted disk into the enclosure. Before swiping my finger, it mounted no volumes (so it appears that any existing data on the drive is wiped out; also the small partition with the software and documentation is gone--I'm not sure how to bring that back, but I don't need it anyhow so it's fine for me). After the...

Tamas, Well it will be a few weeks until I have time to try it. Will let you know how it goes. I'm surprised there is not more information on how to do this; maybe it wasn't a very popular or widely distributed drive? Thank you, Chris