I have a my passport for mac 1TB external hard drive, it has been working perfectly fine until a few days ago when I encrypted it with a password. One day after I encrypted it I typed in the password it would unlock and no problem all files were there and available. The next day I plug it into my macbook and it asks for the password to unlock the disk. I type in the password that is correct (there is no doubt about this the issue does not lie here) and the box that asks for the password vibrates back and forth in the motion that normally suggests on a macbook that it is Incorrect. Then the box is still there and I have tried the following:
- on the second attempt I type in a similar password → The box disappears and the hard disk keeps spinning and there is a light that is sometimes constant and sometimes blinking.
- on the second attempt I typed in a very random password → the box vibrates again on the second try.
The disk did not show up in finder under devices where it would normally show up neither on desktop.
The disk ALSO did NOT show up in disk utility
I then tried to plug it into a different macbook:
The password requesting box did NOT pop up
The disk was not visible under devices in finder
The disk WAS however visible in Disk Utility (while it wasn’t on the other macbook)
The option to mount the disk was a light grey (not possible to click on) I do not understand what mounting the disk means but this might be useful information to someone else.
I clicked on first aid, it took about one second for it to complete and after I clicked continue nothing happened whatsoever. ( I’m not sure if anything was supposed to happen)
Please inform me of all possible options of how to resolve these issues (theoretically and realistically), the files are highly valuable to me and would really want to get them back. I also would like to kindly request everybody to keep the “you should’ve made a backup” to themselves as these are simply pointless comments not going to get us anywhere closer to understanding and solving the problem. 
I am not familiar with hard disks and their physical makeup as well as their software. I would like to get a better understanding of this through this post also to understand what is wrong with mine. Especially keen to know whether the problem lies in the encryption of the drive and that the files are stored in a separate part of the disk where I am just simply not able to access them due the encryption problem at this point?
