BAD_SYSTEM_CONFIG_INFO (bug check 0x74) is a registry error. Microsoft gives two causes: the SYSTEM hive, the registry file that holds machine-wide settings such as which drivers and services load, is corrupt, or some critical registry keys and values are missing. Microsoft calls a corrupt hive unlikely, because the boot loader checks the hive as it loads it, so missing or damaged settings are the likelier story: a manual registry edit, or an application or service that damaged the registry.
On Windows 11 and 10, bad system config info usually appears during startup, so expect to work from the Windows Recovery Environment (WinRE) rather than the desktop. The quickest way to choose a fix is to remember what happened just before: a registry cleaner or tweak tool, a power cut during an update, a change in msconfig, or nothing at all.
Find your BitLocker recovery key first; WinRE may need it before any repair below can touch your Windows drive.
Try these first
- Find your BitLocker recovery key before running any repair tool.
- Restart once; if 0x74 returns, start in Safe Mode once and then restart normally.
- If it began right after an update, use Uninstall Updates in WinRE.
- Run System Restore to a point from before the problem; restore points include the registry.
- In the recovery Command Prompt, run bcdedit /enum {default}; if it lists numproc or truncatememory, remove them (steps below).
- Don’t copy the RegBack folder over your registry without checking its file sizes first.
What happened just before? Pick your starting point
| What happened | Likely cause | Start with |
|---|---|---|
| A registry cleaner, “optimizer”, debloat script or manual registry edit | Critical keys or values deleted or changed | System Restore to a point before it |
| A power cut, flat battery or forced shutdown, especially during an update or shutdown | A registry write was interrupted | Safe Mode once, then a normal restart; then Startup Repair |
| A Windows update installed just before | The update, or an install that didn’t finish | Uninstall the latest quality update |
| Number of processors or Maximum memory changed in msconfig’s Boot > Advanced options | Unusual limits stored in the boot entry, a widely reported trigger | Remove them with bcdedit (below) |
| Memory recently added, or other memory-related stop codes in the past | Faulty RAM corrupting data before it’s written | A memory test once Windows runs again |
| Slow starts, freezes, clicking or disk errors lately | A failing drive damaging registry files | Copy data off first, then check the disk |
| Nothing you know of | Any of the above | The repair order in the next section |
Repair order from WinRE
If bad system config info puts the PC in a boot loop, Windows opens WinRE by itself after two failed starts in a row. Our automatic repair loop guide covers other ways in, reading the Startup Repair log and copying files off; this is the order that suits 0x74.
- Unlock the drive. Have the 48-digit key ready; see where to find your BitLocker recovery key. A tool run against a locked drive can’t repair anything on it.
- Safe Mode, then a normal restart. Choose Troubleshoot > Advanced options > Startup Settings > Restart, then press 4. Microsoft’s guidance for 0x74 is to start in Safe Mode and then restart normally. If that doesn’t clear it, Microsoft treats the damage as too extensive, and the next steps restore or rebuild it. If Safe Mode works but a normal start doesn’t, or 0x74 strikes only now and then in Windows, work from inside Windows: check Event Viewer > Windows Logs > System for registry errors that name a hive or key (Microsoft’s first step for this code), untick Number of processors and Maximum memory under msconfig’s Boot > Advanced options, remove any registry cleaner or tweak tool, and run
rstruifor System Restore. - Check the boot entry; it changes nothing. In Command Prompt, run
bcdedit /enum {default}. A numproc or truncatememory line means someone limited processors or memory in msconfig. Removing them (bcdedit section below) is quicker than any restore and undoes nothing else. - Startup Repair, once, if Windows hasn’t already run it.
- Uninstall Updates, if the error started right after one: the latest quality update first.
- System Restore. This is Microsoft’s recommended way to recover from a corrupt registry hive, because restore points include registry information. Pick a point from before the trigger. Personal files stay, but apps and drivers installed after that point are removed. An empty list usually means System Protection was off, but restore points also expire: Windows 11 version 24H2 keeps them for up to 60 days, and the oldest are deleted when their disk allowance fills.
- Offline file and disk checks. Microsoft also suggests making sure the drive has enough free space and running System File Checker. In the recovery Command Prompt, Windows may not be drive C:, so check with
dir C:\Windowsfirst, then runsfc /scannow /offbootdir=C:\ /offwindir=C:\Windowsandchkdsk C: /fwith the right letter. Copy important files off first if the drive is suspect, because chkdsk writes to it. - Reset or reinstall, the last steps on Microsoft’s list: Reset this PC, or installation media to reset or reinstall Windows. Copy your files off first, as the automatic repair guide linked above shows.
Boot configuration fixes with bcdedit and bootrec
Warning: bcdedit and bootrec change how the PC starts. Microsoft cautions that changing some boot entry options can render a computer inoperable. Export a backup of the store first, change only what’s described here, and expect a BitLocker recovery prompt at the next start.
Undo msconfig processor and memory limits
Repair guides widely report 0x74 after someone set Number of processors or Maximum memory under msconfig’s Boot > Advanced options, which store their values in the boot entry. In the recovery Command Prompt:
- Run
bcdedit /export C:\bcdbackupto save a copy of the store. - Run
bcdedit /enum {default}and look for numproc or truncatememory lines. Microsoft documents numproc as using only the specified number of processors, and truncatememory as making Windows ignore all memory at or above a set address. - Remove each one that’s present with
bcdedit /deletevalue {default} numprocorbcdedit /deletevalue {default} truncatememory, then restart.
Rebuild a damaged boot store
The boot configuration store (BCD) is itself a registry-format file, and Microsoft’s own 0x74 debugging example lists it among the loaded hives. Run bcdedit on its own. If it can’t open the store, or the Windows Boot Loader entry is missing, the store needs rebuilding, and the method depends on the firmware.
- UEFI PCs, which includes every PC that meets Windows 11’s requirements: the boot loader path ends in
winload.efiand the store lives on the EFI system partition. Rebuild it withbcdboot, as shown in the automatic repair guide. - Older BIOS-based PCs (path ending in
winload.exe): Microsoft’s sequence isbootrec /scanosand a restart to test; if that doesn’t fix it,bcdedit /export c:\bcdbackup,attrib c:\boot\bcd -r -s -h,ren c:\boot\bcd bcd.oldandbootrec /rebuildbcd, then restart. These commands assume the Boot folder is on C:; in WinRE, check withdir c:\bootfirst.
A rebuilt store contains only the Windows installations the tool finds, so custom entries, such as a second operating system, may need adding back.
Why the old RegBack copy trick usually fails
Many older guides tell you to copy the registry backup in C:\Windows\System32\config\RegBack over the live files. Since Windows 10 version 1803, Windows no longer backs the registry up there automatically: the hive files are still listed, but each is 0 KB, so the RegBack folder is effectively empty. Microsoft’s recommendation for a corrupt hive is a System Restore point instead.
Check first, using the drive letter Windows has in the recovery Command Prompt (it isn’t always C:): dir C:\Windows\System32\config\RegBack. Zero-byte files mean there’s nothing to restore, and copying them over the live hives would make things worse.
If the files have real sizes, the legacy backup has most likely been turned back on, and Microsoft’s startup troubleshooting procedure applies: rename the five hives in the config folder (DEFAULT, SAM, SECURITY, SOFTWARE and SYSTEM) by adding .old to each name, then copy the RegBack copies into config. Before you do:
- Copy the whole config folder to a USB drive so you can put it back, for example
xcopy C:\Windows\System32\config E:\config-backup\ /E /H /C /Iwith your USB drive’s letter in place of E:. - Check the file dates. The copies roll the registry back to that day: drivers and programs installed since, their settings, and local account passwords all revert.
- On a domain-joined PC, the old SECURITY hive also restores an old copy of the computer’s domain password. If that password has changed since, the PC may lose its trust with the domain; our trust relationship failed guide shows the repair.
Rather have a technician sort it out?
This error usually stops Windows at startup, so someone has to be at the PC for the recovery steps; once Windows starts normally again, a technician can connect with your approval to look for what damaged the registry and turn restore points back on. If the computer won’t start, call us and we’ll tell you honestly whether it can be fixed remotely or needs a hands-on repair. Once it starts, a technician can connect with your approval and fix the rest for $59.
Read the status code once Windows starts again
Microsoft marks the first three parameters of 0x74 as reserved; parameter 4, an NT status code when Windows can supply it, is your best clue to what damaged the registry. Look for it in Reliability Monitor or a crash dump (our blue screen of death guide shows both), if Windows managed to save one; a crash early in startup often leaves no record. It may appear sign-extended, such as ffffffffc000014c; the last eight digits are the code.
| Parameter 4 | Microsoft’s meaning | What it suggests |
|---|---|---|
| 0xC000014C | The registry is corrupt: the structure of a registry file or its image in memory is damaged, or it couldn’t be recovered because its alternate copy or log was missing or corrupt | A damaged hive. System Restore, then check the drive and memory so it doesn’t happen again |
| 0xC000014D | A registry I/O operation failed and can’t be recovered; the registry couldn’t read, write or flush one of its files | The drive or file system. Copy your data off, then check the disk |
| Disk status codes such as 0xC000009C or 0xC0000185 | Bad blocks on the disk, or an I/O error reported by the device | A failing drive or loose connection; back up before any repair |
| Not available | Windows couldn’t record a status | Use the trigger table above |
Two related stop codes point the same way: REGISTRY_ERROR (0x51), which Microsoft links to I/O errors reading registry files because of hardware problems or file system corruption, and 0xC0000218, a registry file that can’t be loaded.
Prevent it on every office PC
- Keep System Protection on. It’s Microsoft’s recommended recovery path for a corrupt hive, and it needs restore points to exist. Check a PC by running
SystemPropertiesProtection, or turn it on from an administrator Windows PowerShell window (the cmdlet isn’t available in PowerShell 7) withEnable-ComputerRestore -Drive "C:\". For many PCs, deploy that command as a script through Intune or your management tool. - Make a restore point before any registry change. Before anyone runs a tweak tool, debloat script or .reg file, run
Checkpoint-Computer -Description "Before registry change" -RestorePointType MODIFY_SETTINGSin that same Windows PowerShell window. Windows allows one such point per 24 hours; if it reports that one already exists from that time, that point is your fallback. - Decide on the legacy registry backup. Microsoft documents a value that brings the RegBack copies back:
EnablePeriodicBackup, a REG_DWORD set to 1 underHKLM\System\CurrentControlSet\Control\Session Manager\Configuration Manager, then a restart; Windows then creates a RegIdleBackup scheduled task. It’s a registry change, so export the key first, test on one PC, and only then roll it out through Group Policy Preferences or an Intune script. - Keep recovery keys off the PC. Confirm each BitLocker key is backed up to Microsoft Entra ID or Active Directory before anyone needs it.
- Keep registry cleaners and tweak tools off work PCs. Microsoft lists manual edits and software that corrupts the registry among the causes of 0x74, and changing the registry is exactly what these tools do. Standard user accounts for staff make them much harder to install.
- Several PCs at once? Look for the shared script, tool or update and stop it before repairing machines one at a time.
When it’s hardware, and when to stop
0x74 is usually software damage, but the registry lives on your drive and passes through memory, so corruption that keeps coming back is a hardware warning. Stop and get help when:
- Parameter 4 or chkdsk points at disk errors, or the drive clicks, disappears from the firmware setup screen, or has been slow and freezing.
- The error returns after a successful System Restore or reset.
- Windows Memory Diagnostic or MemTest86 reports errors.
- You don’t have the BitLocker key, or the files on the PC aren’t backed up anywhere else.
Every repair attempt writes to the drive, so on a suspect drive copy your files off first. A PC stuck on this error can’t accept a remote connection, so the first part needs someone at the keyboard; if nobody can be there, an on-site visit can be arranged through vetted local partner technicians as a separate paid add-on, where available. If you’d rather not do the follow-up yourself once Windows starts normally again, looking for what damaged the registry, turning restore points back on and checking the drive’s health is a typical $59 fix through our remote support service, in a session you approve and can end at any time. Replacing a failing drive or memory is hardware work and isn’t included.
Common questions
Can I fix bad system config info without losing my files?
Usually. Safe Mode, Startup Repair, Uninstall Updates, System Restore and the bcdedit fixes all leave your documents alone, though System Restore removes apps and drivers installed after the restore point. Reset this PC with Keep my files keeps documents but removes apps. The real risks are a lost BitLocker key and a failing drive, so find the key and copy files off a suspect drive first.
Does BAD_SYSTEM_CONFIG_INFO mean my drive is failing?
Not necessarily. The causes Microsoft gives for 0x74 are registry problems: missing or damaged keys and values after a manual edit or an app or service that corrupted the registry, and, less likely, a corrupt SYSTEM hive. Suspect the drive when the status code points at an I/O failure or bad blocks, chkdsk reports errors, the drive makes noise, or the error returns soon after a successful repair. In those cases, copy your data off before trying anything else.
Why did bad system config info start after a Windows update?
Updates rewrite large parts of the registry. If the PC lost power, was forced off or crashed partway through, settings can be left damaged or incomplete. Use Uninstall Updates in the Windows Recovery Environment (WinRE) to remove the latest quality update, then try System Restore if that fails. Once Windows starts, let the update reinstall while the PC is plugged in and left alone.
Can I fix 0x74 without a Windows installation USB?
Usually. After repeated failed starts, Windows opens the Windows Recovery Environment (WinRE), which has Safe Mode, Startup Repair, Uninstall Updates, System Restore and a Command Prompt for bcdedit. You need installation media, made on another PC, only if WinRE won’t load, can’t see the drive, or you decide to reinstall Windows from scratch.
Will resetting the PC fix BAD_SYSTEM_CONFIG_INFO?
Usually, because Reset this PC rebuilds Windows and its registry; Microsoft lists it as the next step after System Restore. It’s slow, though, it removes your installed apps, and Remove everything also erases your files. It won’t help if the drive or memory is failing. Try System Restore and the boot-setting fixes first, and copy your files off before any reset.
How do I fix bad system config info without a restore point?
Check the boot entry first: removing numproc or truncatememory with bcdedit needs no backup. Next, look in C:\Windows\System32\config\RegBack. On most PCs those files are 0 KB and useless, but real sizes mean an older copy you can restore. A recent full-image or system state backup can also supply the hive files. Otherwise, copy your files off and use Reset this PC with Keep my files, which rebuilds Windows and its registry but removes installed apps.
Does bad system config info happen on Windows 10 too?
Yes. The stop code, WinRE and the fixes are the same on Windows 10 and 11. Windows 10 PCs are more likely to be older BIOS-based machines, where the bootrec rebuild steps apply. Windows 10 also stopped receiving security updates in October 2025 unless the PC is enrolled in Extended Security Updates, so plan an upgrade once it’s running again.