Issue
Windows repeatedly displays Preparing Automatic Repair, Diagnosing your PC, or Automatic Repair couldn't repair your PC after an update, System Restore, driver change, registry modification, or interrupted recovery operation.
Searchable Windows error codes and exact messages
Automatic Repair and SrtTrail.txt do not have one dedicated error code. Search the exact screen text—Preparing Automatic Repair, Diagnosing your PC, Automatic Repair couldn't repair your PC—plus the displayed code, stop name, file, or the line copied from SrtTrail.txt.
Common codes that can lead into this loop include:
| Type | Searchable identifier | Typical branch |
|---|---|---|
| Windows Recovery | 0xc0000001 — STATUS_UNSUCCESSFUL | Generic Recovery failure; the accompanying file or message is essential. |
| Windows Recovery | 0xc000000d, 0xc000000e, 0xc000000f, 0xc0000034, or 0xc0000098 | Malformed/missing BCD, missing device, missing boot file, missing BCD object, or invalid BCD data. |
| Windows Recovery | 0xc000014c — STATUS_REGISTRY_CORRUPT | Corrupt BCD or system registry hive; use the displayed file path to distinguish them. |
| Windows Recovery | 0xc0000185 — STATUS_IO_DEVICE_ERROR | Storage I/O prevents Startup Repair or Windows from reading a required boot device. |
| Windows stop/status | 0xc000021a — STATUS_SYSTEM_PROCESS_TERMINATED | A critical user-mode subsystem such as Winlogon or CSRSS terminated. |
| Windows Recovery | 0xc0000221 — STATUS_IMAGE_CHECKSUM_MISMATCH | A boot-critical image or driver has an invalid checksum or is corrupt. |
| Windows Recovery | 0xc0000225 — STATUS_NOT_FOUND | A required device or boot object cannot be found. |
| Windows Recovery | 0xc00000e9 — STATUS_UNEXPECTED_IO_ERROR | Unexpected storage I/O interrupts boot or repair. |
| Blue-screen bug check | 0x00000074 — BAD_SYSTEM_CONFIG_INFO | Registry, BCD, or configuration data is invalid. |
| Blue-screen bug check | 0x0000007B — INACCESSIBLE_BOOT_DEVICE | Windows loses access to the system volume during startup. |
| Blue-screen bug check | 0x0000007E — SYSTEM_THREAD_EXCEPTION_NOT_HANDLED | A boot-time driver or system thread throws an unhandled exception; capture the named driver. |
| Blue-screen bug check | 0x000000ED — UNMOUNTABLE_BOOT_VOLUME | The system volume cannot be mounted. |
| Blue-screen bug check | 0x000000EF — CRITICAL_PROCESS_DIED | A critical Windows process stops during startup. |
Also search the complete log reference, commonly \Windows\System32\LogFiles\Srt\SrtTrail.txt. The phrase Root cause found or a named boot critical file is more diagnostic than the fact that Automatic Repair looped.
Applies when
Use this procedure as a decision path when the loop began after a recent Windows or software change and the system drive remains consistently visible and readable.
Does not apply when
Do not use it as a generic collection of commands when firmware cannot see the drive, storage diagnostics fail, or the loop follows a confirmed hardware fault.
Information that may remain unknown
The exact Windows build may remain unknown during initial recovery. The immediately preceding change, Startup Repair result, and any named file or cause in the repair log should be established when possible.
Requirements
- Windows Recovery Environment
- Access to Advanced options
- Command Prompt only for log inspection; the initial recovery steps use supported WinRE tools
Starting position
At the Automatic Repair screen, select Advanced options > Troubleshoot > Advanced options. If Windows never exposes Advanced options, start matching Windows installation media and select Repair your computer.
Confirm the diagnosis
-
Select Startup Repair and allow one complete attempt.
-
If Startup Repair reports that it could not repair the PC, return to Advanced options. Do not run it repeatedly without new evidence.
-
Open Command Prompt.
-
Display the Startup Repair log from the already-identified Windows volume
W::type W:\Windows\System32\LogFiles\Srt\SrtTrail.txt | more -
Record:
- Last successful boot time
- Number of repair attempts
- Any named root cause
- Any named file, driver, disk, or registry hive
- Whether Startup Repair says it performed a repair
-
Treat the log as a lead, not proof. Match it to one of the branches below.
Resolution steps
Follow only the branch supported by the timing or evidence.
Branch A — Loop began immediately after a quality update
- Return to Advanced options.
- Select Uninstall Updates.
- Select Uninstall latest quality update.
- Allow the operation to complete without forcing a shutdown.
- Restart and test Windows.
Branch B — Loop began during or after a feature-version upgrade
- Return to Uninstall Updates.
- If Uninstall latest feature update is offered, select it.
- Complete the rollback and restart.
- If the option is unavailable, do not substitute random package-removal commands. Move to System Restore or the logged driver branch.
Branch C — A usable restore point predates the problem
- Select System Restore.
- Choose the most recent restore point created before the triggering change.
- Review the affected programs before confirming.
- Complete the restore and restart.
Branch D — A specific recently installed driver is implicated
- Select Startup Settings > Restart.
- Choose Safe Mode.
- If Safe Mode starts, open Device Manager.
- Locate only the implicated device.
- Use Properties > Driver > Roll Back Driver when available.
- If rollback is unavailable and the driver is nonessential, uninstall that device without selecting permanent driver-package removal on the first attempt.
- Restart normally.
Branch E — SrtTrail identifies BCD or EFI boot files
Use FIX-003 or FIX-004 after independently confirming the partition and BCD condition. Do not rebuild BCD solely because Startup Repair failed.
Branch F — SrtTrail, CHKDSK history, or behavior indicates storage errors
Stop automated repair attempts. Check firmware visibility and storage health using FIX-005. Preserve data before a write-heavy file-system repair.
Branch G — No cause is isolated
- Try Safe Mode through Startup Settings.
- If Safe Mode starts, perform a clean boot:
- Run
msconfig. - On Services, select Hide all Microsoft services.
- Disable the remaining third-party services.
- Disable startup applications through Task Manager.
- Run
- Restart normally.
- Re-enable items in groups until the loop returns.
Expected results and branches
- Windows starts after uninstalling an update: The update or its interaction with a driver is the leading cause. Do not immediately reinstall it without reviewing the failure.
- System Restore succeeds: Verify several boots before declaring resolution.
- Safe Mode works but normal mode fails: A nonessential driver, service, or startup component is more likely than BCD damage.
- Neither Windows nor matching recovery media can read the disk reliably: Stop and investigate storage hardware.
- SrtTrail names no root cause: Do not treat the log filename itself as the error.
Do not do this
- Do not delete
SrtTrail.txt; it is a log, not the cause. - Do not disable Automatic Repair as a permanent “fix.”
- Do not run
bootrec, CHKDSK, SFC, DISM, and registry restoration indiscriminately in one sequence. - Do not copy empty or unrelated RegBack files over active registry hives.
- Do not reset or reinstall Windows before the narrower recovery branches have been evaluated.
Rollback
Use System Restore to reverse driver or service changes made during troubleshooting. Re-enable clean-boot services and startup entries in the same recorded groups if they prove unrelated. An uninstalled update can be reoffered later after the underlying compatibility issue is understood.
Verification
- Windows starts normally three times.
- Startup Repair no longer launches automatically.
- Event Viewer does not show the same boot-critical failure on each start.
- The triggering driver, update, or service remains removed, rolled back, or corrected.
- Sleep/wake and a cold boot both succeed.
Confidence and stop conditions
Confidence is approximately 80% for this evidence-driven decision path, not for any single branch before its trigger is established. Stop if the disk is intermittent, the log identifies a registry or file version that cannot be matched safely, or every supported rollback option fails.