If the firmware is up to date, then perhaps you could try with a static IP configuration in the Dashboard in order to ensure the device will keep a set connection.
Perhaps I should, but as it was working fine before I am a bit confused as to why I need to spend ages trying to configure what is billed as a plug and play device. If I wanted to spend hours tinkering with it I would have bought a professional bit of kit.
I have disabled indexing and that has helped a little bit, but has not fixed the problem. Of course if the interface was even vaguely responsive I might be tempted to try, but as it isn’t…
If you can, do a system restore in Dashboard > Utilties. This will format and reinstall the OS of the drive with the current firmware you have installed. Also make sure you are only connected through wired (disable wireless) when you transfer files.