Hi.
I just had the same issue with my Explora 2 and thought it would be a nice challenge to try and fix it myself.
I removed the hdd from the decoder and plugged it into a pc running Linux. I could see some errors on the drive in Linux so I knew the crappy Toshiba drive was packing up.
I saw that the 1 TB drive had 2 partitions on it, one is 10 GB (I assume for live recording and rewinding) and one is 990 GB (Recordings, DSTV Now, Box Office).
Please note that windows will not recognize the drive as it is a Linux drive with a Ext4 file format
Next I took a new HGST (Way better that Toshiba, though a bit more expensive) 1TB drive and created 2 partitions, one 10 GB and one 990 GB.
I formatted them with Ext4 file format in Linux and installed the drive back into my decoder.
It worked 100%