45min Boot Screen

Possible Fixes for High Sierra

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to backup your files before proceeding if possible.

1. Shutdown the computer, wait 30 seconds, restart the computer.
2. Resetting your Mac’s PRAM and NVRAM
3. Reset the System Management Controller (SMC)
4. Start the computer in Safe Mode, then restart normally. This is slower than a standard startup.
5. Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
6. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button below Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
7. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
8. Erase and Install OS X Restart the computer. Immediately after the chime hold down the CommandandRkeys until the Apple logo appears. When the Utility Menu appears:

1. Select Disk Utility from the Utility Menu and click on Continue button.
2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
4. Set the Format type to Mac OS Extended (Journaled.)
5. Click on the Apply button, then wait for the Done button to activate and click on it.
6. Quit Disk Utility and return to the Utility Menu.
7. Select Install OS X and click on the Continue button.

You can search this site for other reports of that lugubrious message: Mac not booting, stuck on start screen despite disk repair. There is no definitive resolution to it, which leads me to surmise a Genius Bar appointment will be required. Schedule it to occur a couple of weeks from today.

If you can get into Safe Mode then run EtreCheck. It's a diagnostic tool that's very useful to us in finding problems. Also it will give us further specs on your Mac. After it runs post the log file here. It will contain no personal information.

If you can't boot into Safe Mode (and 45 minutes seems too long) the boot into Recovery (command-r) and run Disk Utility > First Aid on the hard drive and let us know what it reports.

All the symptoms you describe suggest hardware failure, probably its hard disk drive or Fusion Drive if your MBP is so equipped. There is nothing else you can do other than to reinstall macOS, which also may not work (edit: I see it did not). Do you have a Time Machine or equivalent backup?

Can SMART diagnostics be accesed in the recovery console?

No. You can try Apple Diagnostics / Apple Hardware Test but only a report identifying a specific failure can be considered a conclusive result. In other words "no trouble found" does not definitively mean no trouble exists.

Contact Support

Thanks for posting your solution. Glad it's sorted!