Mac – What does Converting (forward) mean in diskutil


I had an APFS (Encrypted) disk which I chose for Time Machine backups on macOS Catalina.

I was asked if it was OK to erase the disk (Time Machine on macOS Catalina dosen't support APFS).

I answered yes and disk was formatted as "Mac OS Extended (Journaled, Encrypted)".

Initial backup is done, but encryption is taking forever.

Running diskutil cs list reveals Converting (forward) and Conversion Progress: 2%.

What does Converting (forward) mean and was my data backed up in clear (meaning it was encrypted during initial backup)?

Why is it taking forever to encrypt data given disk was formatted as "Mac OS Extended (Journaled, Encrypted)" before data was backed up?


Best Answer

Converting "forward" means that direction is from not encrypted -> encrypted. I.e. you started with a blank disk and enabled encryption.

It is possible to do a conversion in the opposite direction if you later decide you do no want your disk to be encrypted.

Your backup was encrypted - it is not stored in the clear when encryption is enabled.

Encryption does take a long time, yes. It is intentionally throttled to not consume system resources, but takes place in the background. You can keep using the computer and the disk while it is working.

It can be a pain if you're encrypting an external disk and need to keep it connected for a long period of time, but unfortunately that is normal.