I have the SATA HDD from my old, all-but-dead laptop in a USB 2.0 docking station. I want to copy ~50 GB of data from it onto an external USB 3.0 HDD. I'm running Windows 8, but it seems to have trouble recognizing the partition on my SATA drive that contains the data I need (there are 3 partitions, and the bootable one with the old laptop's OS contains my data; it's also the largest partition). When I plug the docking station into a USB 3.0 port, Computer shows all 3 partitions on that drive, and it lets me explore 1 or both of the other partitions, but not the one I need, and the Disk Manager fails to load (it hangs at "Connecting to Virtual Disk Service..."). When I plug it into a USB 2.0 port, Windows shows me no new drives in Computer or Disk Manager, although it plays the "new hardware connected" sound. Therefore, I turned to an Ubuntu Live CD.
Sometimes the partition I need will mount successfully in Ubuntu without me having to do anything, while other times I have to follow this (and then sometimes it mounts after the "mkdir /media/disk" command, oddly enough). In either case, I am eventually able to explore that partition. Once I begin copying data, however, the data transfer speed shown constantly decreases up to a certain point. On my first attempt, it decreased until it was around 80 kbps (I then canceled because it was too slow). On my second, it decreased until it was around 120 kbps.
This means, as the "time remaining" indicates, that it will take several days to copy my data, which definitely should not be the case. On the second attempt, it copied ~20 GB of data over the course of almost 2 days, and then I found my computer no longer copying files but displaying a message about low disk space on my internal HDD (it said I had ~800 MB left). After clicking "Ignore," I then got another message about low disk space, this time saying I had 0 bytes left. The size of the partition on the USB HDD that I'm copying to is 170 GB, so it is more than big enough to hold all the data, and I don't see how the space on my internal HDD would be at all affected since I'm copying the data directly from the docking station to the USB HDD. I'm beginning to think that the data may have stopped copying because of a possible brief power outage (I'm told that there MAY have been one while I was asleep), as the docking station uses an AC adapter.
What's going on? Why is the transfer speed so horribly slow? Does it have anything to do with running Ubuntu off of a DVD (since the computer has to "consult" with the DVD as well as deal with 2 USB devices)? Why would space on my internal HDD become low during the copying process? If not due to a power outage, why would it have stopped copying prematurely? Is there any way to force the drive to mount in Windows 8 when Disk Manager won't load? What's the best and fastest way to copy my data over? I know that a USB 3.0 docking station / external enclosure would be much faster, but I just received this one as a Christmas gift, and don't want to get a new one unless it's really necessary. There are only 4 folders I want off of the old drive, so I don't want to just do a clone of that partition; it would take even more time to copy over unnecessary data, and might also copy whatever is keeping the drive to mount.