Fix ERROR_NO_SUCH_PACKAGE (0x554) in Windows Login

Cause #1: Broken Registry Entry for Authentication Packages

I know this error is infuriating—you're just trying to log in and Windows throws a cryptic code. The most common culprit is a corrupted or leftover entry in the registry under HKLM\SYSTEM\CurrentControlSet\Control\Lsa. This key lists the authentication packages Windows loads at boot. If one points to a DLL that doesn't exist (or got deleted), you get 0x554.

This happens a lot after uninstalling third-party security software, especially VPN clients or password managers. I've seen it with old versions of Symantec Endpoint Protection and even some Cisco AnyConnect installs. The uninstaller removes the DLL but leaves the registry entry behind.

Backup first, then fix the registry

Before you touch anything, export the Lsa key. One wrong move and you'll have bigger problems.

1. Press Win + R, type regedit, hit Enter.
2. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa.
3. Right-click Lsa and choose Export. Save it as a .reg file somewhere safe.

Now, look at the Authentication Packages and Security Packages values (they're REG_MULTI_SZ). Each line should be a valid package name like msv1_0 or kerberos. If you see anything odd—like a vendor name or a random string—that's your problem.

To fix, double-click the value, remove the bad lines, and keep the standard ones. For most systems, msv1_0 is the only one you need in Authentication Packages. For Security Packages, you'll typically see kerberos, msv1_0, schannel, wdigest, tspkg, and pku2u.

After editing, restart. If you still get the error, repeat and check for any duplicate entries.

Cause #2: Leftover DLLs from Uninstalled Security Software

Even if the registry looks clean, a stray DLL that Windows tries to load might be missing or corrupted. The error often shows up when the LSA (Local Security Authority) tries to load a package file that no longer exists. This is the “specified authentication package is unknown” part.

I once spent an afternoon chasing this on a Windows 10 machine after a failed antivirus removal. The registry was fine, but a DLL named authpkg.dll was half-deleted. Windows saw the entry, tried to load the file, and choked.

Find and remove the offending package

First, check which packages are listed in the registry (as above). Then look in C:\Windows\System32 for those DLL files. If a listed package has no corresponding DLL, that's your issue.

If you find a missing DLL, you have two options:

• Restore the DLL from a backup or the original installer.
• Remove the registry entry that references it.

The safer bet is usually to remove the entry, unless you know the package is required (e.g., if you're in a corporate domain, don't remove kerberos).

To check for corrupted DLLs, run a system file check:

sfc /scannow

Let it finish. If it finds issues, restart and test. If it doesn't, move on.

Cause #3: Corrupted LSA Configuration from Third-Party Tools

Sometimes the issue isn't a specific package but the whole LSA configuration. Tools that modify security policies—like some “tweaking” utilities or enterprise management agents—can leave the LSA in a broken state. I've seen this with certain older versions of Dell Data Protection and even some printer drivers that install authentication hooks (yes, really).

The fix here is to reset the LSA configuration to Windows defaults. You can do this with the registry or with a command-line tool.

Reset LSA using the command line

Open an elevated Command Prompt (right-click Command Prompt, choose Run as administrator). Then run:

reg delete "HKLM\SYSTEM\CurrentControlSet\Control\Lsa" /v AuthenticationPackages /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Lsa" /v AuthenticationPackages /t REG_MULTI_SZ /d msv1_0 /f
reg delete "HKLM\SYSTEM\CurrentControlSet\Control\Lsa" /v SecurityPackages /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Lsa" /v SecurityPackages /t REG_MULTI_SZ /d kerberos\0msv1_0\0schannel\0wdigest\0tspkg\0pku2u /f

That sets the standard packages. The \0 is how you separate values in a multi-string from the command line. Restart after this.

If you're not comfortable with the command line, you can do the same in Registry Editor—just replace the values with the ones I listed above.

Quick Reference Summary

If none of these work, consider a system restore to a point before the error started. And if you're in a domain environment, check with your admin—sometimes group policy pushes a bad package. You're not alone in this, and it's fixable.