Help: need to rescue files on my external hard drive after using Time Machine

[Kangyu]

I just lose my partitions on the same disk after reseting one partition for Time Machine.

I have an external hard drive with 1 TB, and I made it two partitions:

- one is for some data (named `Resources`);
- one is for Time Machine (named `TimeMachine`).

The partitions are HFS+ format, and I use this setup for many years.

Today, the partition for Time Machine can't be found by Time Machine with my latest macOS Big Sur. It doesn't show in the list of `Select Disk`. So I decide to "reformat" the partition `TimeMachine` in Disk Utility with HFS+ format again. After "erasing" the partition, it can be found by Time Machine again, and I still keep the files on the other partition `Resources`.

Then the terrible things happened. The Time Machine make a notification said "found a disk for Time Machine"; I follow the hint to enter a password to setup for Time Machine, then the whole disk is reformatted into APFS, and It has no any partitions. I lose all partitions and files in the partition `Resources`.

I just want to setup one partition for Time Machine, but it erases and reformats all disk without asking me.

Now I just want my files back. I know my files are not missing. It just loses the index table for finding them on my disk.

How to rescue my files on my external hard drive? Please help me.

 

[Fishrrman]

If the whole disk has been "reformatted" into APFS (when it was HFS+ before), I'm guessing that there is a high probability that the files that were on the HFS+ partition are now gone.

I don't think you're going to have much luck getting them back.

As for the future, don't mix a TM backup with any other drive.
I wouldn't use TM anyway -- you see what it did to you here.

Use a REAL backup utility like CarbonCopyCloner or SuperDuper instead.

And in the future, when you store important data on an external drive...
... you MUST keep a SECOND external drive to serve as a backup for the first one.

Or else, bad things can happen...

 

[svanstrom]

If the whole disk has been "reformatted" into APFS (when it was HFS+ before), I'm guessing that there is a high probability that the files that were on the HFS+ partition are now gone.

Probably not, but I'm not familiar with what actually happens when you switch from HFS+ to APFS.

A simple "reformatting" usually doesn't overwrite the existing data, it simply drops the old coordinates for where things are stored; and make up new ones that says that nothing is stored anywhere.

That's why businesses always use specialists for data destruction, because data is sticky as heck; not even basic overwrites can remove it properly.

An average user can't just reconnect a drive and hit "recover"; but data recovery specialists often can do just that.