Chosen Solution
My computer just shut down due to power cut. Then it just opens to password menu, after that it says to reinstall os from internet by downloading. And the download never completes. It just stops. What to do? Facing the issue since 2016, i have some important photos, files which i want at any cost. Is there anyway to get those files if can’t open it again ?
Try booting macOS from an external drive and see if you can recover the files from your internal drive. If you have another Mac, you can make a bootable usb from the High Sierra installer app. Boot from the USB, and install macOS to an external HDD.