Question Hard drive disappearing from system when in use?

[jordanrevell59]

I was updating games on steam when an unexpected scenario occurred. The hard drive was apparently not recognised after updating three games individually, as a result i restarted and it opened BIOS. After multiple attempts to start up, even reconnecting the HDD,it booted. The computer started normally and allowed windows to boot etc. When i tried to open a game, steam stated i needed to reinstall the games on the Hard drive. Moreover, files listing: System, System64 and Mono were present in the drive when never before, also including a Windows installer Package (.msi). I have an external SSD to which Windows 10 PRO is installed on.
Can anyone help with what the folders of files are, and what actions i should take?

EDIT: games were re verified, however why were those files placed here and should i remove them?

The images show the evidence.

 

[RealBeast]

I would download and run the HDD manufacturer SMART tests to insure the stability of the drive to begin with,

 

[Md Noman 1]

I was updating games on steam when an unexpected scenario occurred. The hard drive was apparently not recognised after updating three games individually, as a result i restarted and it opened BIOS. After multiple attempts to start up, even reconnecting the HDD,it booted. The computer started normally and allowed windows to boot etc. When i tried to open a game, steam stated i needed to reinstall the games on the Hard drive. Moreover, files listing: System, System64 and Mono were present in the drive when never before, also including a Windows installer Package (.msi). I have an external SSD to which Windows 10 PRO is installed on.
Can anyone help with what the folders of files are, and what actions i should take?

EDIT: games were re verified, however why were those files placed here and should i remove them?

The images show the evidence.

First back up your important data i have had a hard drive fail on me in similar way lost my important data not good situation to be in.Then do a scan for bad sectors then go from their.

 

[jordanrevell59]

First back up your important data i have had a hard drive fail on me in similar way lost my important data not good situation to be in.Then do a scan for bad sectors then go from their.

I've scanned using the manufactures smart program, however the extended scan stated that the HDD was completely fine in all sectors? To add, starting up the computer the HDD is present, but while updating a game, the drive removes it self from the system immediately i.e. task manager and file explorer. I can run programs and such to where the drive is being utilised. Any suggestions?

 

[jordanrevell59]

I would download and run the HDD manufacturer SMART tests to insure the stability of the drive to begin with,

I ran an extended test on the manufacturers smart scan and came back all positive, i can run games on the HDD but cannot download any updates for the drive to immediately stop the update and remove its self from the system, and just played a game on the HDD to after exiting the game and the HDD to remove its self once again.