It could cause data loss if the external hard drive keeps disconnecting while transferring data. Therefore, rescue your drive data first and then fix the issue by checking the connection, restarting your Mac, booting into safe mode, etc.
There are many possible reasons for an external hard drive to keep ejecting on your Mac. It may relate to the defective USB cable, port, or hub, software, hardware issues on your Mac, corrupted external hard drives, and so forth.
To avoid further data overwritten when the external hard drive keeps disconnecting on your Mac, you can use the professional data recovery software - iBoysoft Data Recovery for Mac to recover the valuable data on the abnormal external hard drive before you proceed to fix it.
Steps to recover data from the external hard drive that keeps disconnecting on Mac:
- Download, install, and launch iBoysoft Data Recovery on your Mac.
- Connect the external hard drive to your Mac.
- Select your external drive and click Search for Lost Data.
- Filter and preview recoverable files.
- Tick the files you want to recover and click Recover to save them to a different location.
Then, apply the following methods to fix the external hard drive keeps disconnecting issue on your Mac:
- Plug the drive back in again.
- Restart your Mac
- Disable the setting "Put hard drives to sleep when possible."
- Change between a direct link and a hub
- Set the maximum disk sleep time as the default
- Turn off or remove the third-party antivirus software
- Boot into Safe Mode
- Utilize Disk Utility's First Aid to fix the disk.
- Downgrade or upgrade macOS
- Data recovery and disk formatting