Disk Assistant using the steps:
1. Open Disk Assistant.
2. Interface automatically refresh, You can scan the local disk.
3. If Disk Assistant can not run,See the next step.
4. System Preferences -> Security & Privacy, Please select: "Mac App Store and identified developers".
MacOS recovery mode backup disk, recover lost files:
1.MacOS into the recovery mode, long press Command + R, and then press the power button until the progress bar appears, then release Commang + R key, successfully entered the recovery mode as shown below:
2. Start the terminal command line tool, as shown below:
3. Into the disk assistant folder, start the disk assistant, as shown below:
The following operation command:
4. After you successfully start Disk Assistant, there are two ways to recover lost data:
a、Backup partition or disk, after the backup, restart the computer, load the disk image file recovery lost files.
b、In another computer running data recovery software, enter the IP and port, click the "Connect" button, the connection is successful, you can recover the lost files.
Successfully connected as below: