Is it safe to just yank an external hard drive if you know nothing is writing to it?

Yes, I know somewhat about the possibility of data corruption if there was data that hadn't been all written to it.

But I just saw this:

Note:If u remove HDD(not USB sticks) without safely removing it,its not healthy and will affect life.

So, if nothing is actually writing to it, could there actually be any harm caused by not safely removing or unmounting it before disconnecting it?

Solution 1:

No! Cached data may not be written yet. Regardless of your OS, you have to inform it that you're yanking.

OSes do write-caching (and read-caching) to make drive access faster.

Solution 2:

When you run the safe removal process, commands are sent to the disk to cause it to spin down and park the heads: in contrast if you disconnect the power suddenly then an emergency unload is done, which uses remaining power to move the heads away from the surface. That movement is violent and so disks are rated for a far fewer number of emergency unloads than the standard parking of the heads. So by pulling the power you may indeed be causing physical damage to the actuator mechanism.