"Preparing Automatic Repair" loop: Windows will not start

Windows tried to repair itself at start-up and failed. The recovery screen it lands on has the tools to get you out.

What you seePreparing Automatic Repair ... Diagnosing your PC ... Automatic Repair couldn't repair your PC

What is happening

When Windows fails to start twice in a row, it launches Automatic Repair. Usually that fixes the start-up files and Windows loads. In a loop, the repair itself fails or the cause lies elsewhere: a bad update, a damaged system file, a driver, or a failing disk. You then see "Automatic Repair couldn't repair your PC" with two buttons: Shut down and Advanced options.

First, the simple checks

1. Unplug every USB device except keyboard and mouse: drives, phones, card readers, printers. Then restart.
2. Hold the power button for ten seconds to switch off fully. On a laptop, unplug the charger, wait a minute, plug in and start.
3. Give one start-up fifteen minutes before deciding it is stuck. After a large update, "Diagnosing your PC" can take a while.

Work through Advanced options

Click Advanced options › Troubleshoot › Advanced options. Try these in order, restarting after each.

1. Startup Repair. Run it once more by hand. It sometimes succeeds on the second pass.
2. Uninstall Updates › Uninstall latest quality update. If the loop began after an update, this is the likeliest cure. Try "feature update" only if the quality update did not help.
3. System Restore. Pick a restore point dated before the trouble. Your files are not touched. See System Restore.
4. Startup Settings › Restart, then press 4 for Safe Mode. If Safe Mode loads, uninstall the last driver or program you added, then restart normally. See Safe Mode.
5. Command Prompt. Run a disk check and a system file check. In the recovery environment the Windows drive may not be C:, so first find it:

dir C:\Windows
dir D:\Windows

Use the letter that lists the Windows folder in the commands below (C: is shown here).

chkdsk C: /f
sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows

If start-up files are damaged, rebuild them:

bootrec /fixmbr
bootrec /rebuildbcd

These two change only the start-up records, not your files. bootrec /fixboot may answer "Access is denied" on modern computers; that message can be ignored if the other steps succeed.

If the loop continues

• Reset this PC › Keep my files (under Troubleshoot) reinstalls Windows and keeps personal files, but removes programs. See Reset this PC.
• If Reset fails too, Windows can be reinstalled from a USB stick made on another computer with Microsoft's Media Creation Tool, from the official Microsoft website.
• Before any reset, rescue your files if you have no backup: in Advanced options › Command Prompt, type notepad, choose File › Open, and use that window to copy folders from the disk to a USB drive. It is slow but it works.

If the disk is not found at all

If chkdsk says it cannot open the volume, or the Reset screen says the drive is locked or missing, the disk may have failed or come loose. See boot device not found.

For Windows 11 and Windows 10. Written in November 2026. Menus move between updates; use the search box in Settings if a name differs. Back up important files before any step that resets, repairs a disk or opens the computer. This is an independent guide, not connected with Microsoft.