My external hard drive came up with a message yesterday which told me that the disk needed to be checked. It's done this several times recently and then just run the check. Which usually takes several hours. Afterwards it has continued to work as normal.

This time though, the computer appeared to abandon the check after about twenty minutes and instead I got a message saying "Drive not accessible. Acess denied."

The external hard drive icon still appears in the computer window, although the Total size and Free Space volumes show up as blank.

Everything is backed up, so there's no loss of data. However, if anyone knows how I can get the drive working again, I'd be most obliged.