Fix hard disk not detected after force eject I got an HDD on my Mid 2012 Macbook Pro 13 inch. I decided to upgrade to SSD and I want a clean install of El Capitan. After the SSD ugprade and OS installation I connect my old HDD as an external storage thru USB. After copying the files from the old HDD, I want to eject the HDD but it won't allow and the system shows a message that something is using the HDD and give me an option to force eject. So I force eject the HDD. After a while, I need to connect again the HDD to copy some files, but this time around the HDD is not anymore detected. I'm sure the external closure is fine because it can detect other HDD when I try to replace it.
When execute the diskutil list, I got the results below. But HDD is not listed on the Disk Utility window. I read that the HDD maybe corrupted (External hard disk not showing up on finder and can&#39;t be verified in Disk Utility). Is there still a way to fix the HDD?

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage SSDCrucial01            499.2 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS SSDCrucial01           +498.9 GB   disk1
                                 Logical Volume on disk0s2
                                 D54522C3-5817-4D10-A1C8-C35193CA2F78
                                 Unencrypted
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS Macintosh HD            499.2 GB   disk2s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk2s3
The only i way i Fixed my HDD when i forced ejected is to do as Pelang said. PRAM reset and wait 3 sounds. It really important to plug your HDD while doing that PRAM reset, after 3 sounds its going to fix it.