At some point in your life, after you connect your external hard drive, you will hear something unpleasant. Your external hard drive makes clicking sounds as it begins to start up or as you are reading data from it and that means that it"s reaching the end of its life or that it has serious problems. It"s when you should try to save your data or fix it altogether.
A USB hard drive clicking is a very common occurrence these days because many hard drives out there these days are made cheaply by manufacturers who don"t worry about quality. You"ll probably never hear Western Digital external hard drive clicking or Seagate external hard drive clicking, but other brands like Hitachi and Samsung have notoriously shorter life spans and you should avoid them if you want to avoid a portable hard drive clicking.
As soon as you hear external hard drive clicking noises, you should consider stop using that hard drive normally and prepare to backup the files in it. Stop using that hard drive to write and files and avoiding reading files like movies and music. Instead, get a program like Active@ Data Recovery so that you can use it to efficiently recover your data from the faulty hard drive having less chances of losing all of it.
You should avoid handling your external hard drive roughly at any time, since that can cause the clicking. Avoid letting it fall to the ground, don"t turn it off from the USB plug while reading and writing files, don"t hit it too hard. Each time you do something like that you risk that the external hard drive keeps clicking next time you plug it in.
If you are unable to save all of your data from the hard drive before it crashes, you should take it to a professional specialist so that they can try to fix at least partially the hard drive clicking. They may not fix the hard drive entirely, but they should be able to put it minimally functional so that you can recover all of your data before the hard drive ceases to function entirely.
Even if the hard drive stops clicking after repair, don"t trust too much on it. A clicking external hard drive once showing the error is never again reliable and even if you use it you should put non-critical data in it only, otherwise you may lose that data suddenly when you least expect. Consider buying a new external hard drive as soon as possible and use that one instead.