Operation failed with status 5

Try running the Apple Diagnostics to see if the hard drive may be starting to fail and to look for other possible hardware issues.

It's possible your hard drive is beginning to fail. It's also possible the internal hard drive SATA cable is defective which is extremely common on this model. There are several things you can do to try and recover your data:

• Install macOS to an external drive so you can boot the laptop to the external drive to make it easier to recover your data.
• Boot to Recovery Mode or Internet Recovery Mode and use the Terminal app to backup your data if you are familiar with the command line.
• If you have access to another Mac you can either put this laptop into Target Disk Mode or you can remove the hard drive and use a USB to SATA Adapter, drive dock, or enclosure.

If you can boot macOS, then you may want to check the health of the drive before trying to recover any data. If the drive is beginning to fail, then it may affect how you can recover the data or you could make the failure worse. Run DriveDX to check the health of the hard drive. Feel free to post the report here using the "Additional Text" icon which looks like a piece of paper.

Elsygd wrote:

Thank you!

where can I find Apple diagnostics?

I downloaded Sierra in my external drive directly from Disk Utility, and when my Mac restarted it worked great, but I had to create a new account and reset everything. When I finally logged in, there was absolutely nothing - no documents, Pictures, nothing.

what am I doing wrong?

Does this mean you successfully installed Sierra to the external drive? If so when you log into the new account it will be empty. Make sure the Finder preferences are configured to show mounted volumes. If Finder is configured to show mounted volumes and you don't see your original internal drive, then I highly recommend you run DriveDX to check the health of the hard drive. Post the DriveDX report here using the "Additional Text" icon which looks like a piece of paper.

If the hard drive appears healthy, then you can try running Disk Utility First Aid on the internal drive to try and fix any file system errors. You may need to run First Aid on the physical drive as well which may require you to click on "View" within Disk Utility and select "Show All Devices" before the physical drives are shown. If First Aid doesn't show any errors, then try using Disk Utility to mount your internal drive volume.

“macOS could not be installed on your computer. An error ocurren

installing macOS. To use Apple Diagnostics.... Quit the installer to

restart your computer and try again.”

This tells me you likely have a failing hard drive or possibly a defective hard drive SATA cable.

Your best option is to boot an external macOS drive as it allows you a full working OS to try and troubleshoot and salvage your data. I highly recommend getting the health status of the internal drive because if it is going bad, then the more you try to do will just accelerate the drive's failure to the point where even a professional data recovery service will be unable to recover the data.

It really sounds like you have a failing hard drive. The more you attempt to use it the worse the failure will get. Unfortunately standard apps & utilities are unable to handle the errors being produced so it causes you to try over & over which is just making the problem worse.

See if you can run DriveDX and post the report here using the "Additional Text" icon which looks like a piece of paper.

From everything you've posted I think the failure has gone beyond what even an app like Carbon Copy Cloner can handle for backing up your files. If the drive is producing lots of I/O errors, then the only way to retrieve the data yourself is by making a bit for bit clone of the drive which will require a command line Linux utility and boot disk as well as an external drive of equal or larger size than the bad internal drive. I don't even try to use macOS to clone a failing drive because macOS gets in the way. Then you work from the clone which is using a good drive without physical errors to try and retrieve your files.

I use a Linux system with the command line utility GNU ddrescue to perform a bit for bit clone since this utility can skip past the bad sections of the drive to concentrate on recovering data from the good sections first. It also is able to resume an interrupted clone if the "logging" feature is used. Care must be take though or you could accidentally overwrite the data on the bad drive especially when resuming a clone. You can create a bootable Knoppix Linux USB drive using Etcher (Mac/Windows/Linux). Option Boot the USB drive and select the orange icon labeled "EFI". While Knoppix is booting the computer may appear to be frozen on the boot picker menu so give Knoppix lots of time to boot. Knoppix includes the GNU ddrescue utility.

You can also check the health of the hard drive using Knoppix. Once Knoppix boots to the desktop click on the "Start" menu on the lower left of the Taskbar and navigate the menus to "System Tools ---> GSmartControl". Within the GSmartControl app double-click on the laptop's hard drive icon to access the drive's health information. Post the full report here.

If the data is important enough, then I highly recommend you contact a professional data recovery service such as Drive Savers or Ontrack. Both vendors provide free estimates and both are recommended by Apple.

You will only get one chance at recovering data from a failing hard drive so choose wisely.

Edit: I should add since you have a 13" mid-2012 model that the internal hard drive SATA cable could be causing errors as well. Getting the health report for the drive is essential in knowing how to proceed in order to recover the data. You could try removing the drive and connecting it externally to see if the errors disappear, but I really recommend using one of the options to get the drive's health report and minimize the use of the drive until its health has been determined.

Well, in pure Apple File System talk... -36  ioErr  I/O error (bummers)

Not very helpful, but generally means a Drive quit being Readable or Writable since starting the operation...

http://fuzzy.wordpress.com/2006/12/10/ioerror-36/

Did you migrate any data from a Backup?

I'm out of ideas at the moment...