How long does it take to encrypt a 4TB drive?

Sounds about right to me with my experience encrypting a 4TB WD Elements hard drive.

 

at least 36 hours. maybe even 72 hours.

it does depend on what your connection is: wired or wireless. and if its wired, is it USB3.? what standard, etc etc.

wireless can take days, and at the end of it finish with an error message.

 

3.0 vs 3.1 is about a day or so difference in time.

 

that's the point.
that's what i also discovered in the past:
i have started to use a drive for Time Machine but decided later to encrypt it.
takes forever and ever and ever and ever.
even if there is NOTHING on the disk.
therefore, what i have learned is its just better and MUCH quicker (were talking minutes vs days) to just quit the entire process. and format it from the beginning with encryption from the very first. very quick if done that way, vs. later applying encryption to an even "empty" drive.

 

Day 4 of encrypting a new 1TB Seagate external hard drive in the Time Machine setup process on a 2016 MacBook Pro. I’ve been letting it run 7x24. Only 66% done. I didn’t know one could encrypt it first before setting it up for Time Machine.

 

Converting a previously unencrypted drive to an encrypted drive requires a sector by sector encryption and secure wiping process. HDDs don't "delete" data when you delete it instead the pointer to the data is removed from your file system. Without the previously mentioned process a raw HDD read could expose previously unencrypted data on an encrypted drive.

 

Forensic tools exist that can extract and analyse disk contents sector by sector, whether the content is encrypted or not. So making sure that every sector is encrypted is the way to go.

 

Can anyone explain what the difference is between these two processes? Is a disk better encrypted (i.e. more secure) if you encrypt it later after saving contents to it versus formatting it and encrypting initially before saving files to it?

 

You can interrupt the encryption process by gratefully dismounting the drive. You don’t need to encrypt the entire thing in one shot.