How To Fix the LSA Module Blocked Error on Windows 11

Ah, the classic “This module is blocked from loading into the Local Security Authority” error. It’s kinda frustrating because it pops up mainly when Windows’s security protections get a bit paranoid — especially in Windows 11 version 24H2 and newer. Basically, Windows is trying to keep malicious modules out, but sometimes legit ones like mdnsNSP.dll from Apple’s Bonjour get caught in the crossfire. If you’re seeing this error pop up, chances are it’s because Bonjour — which is used for network printing and some Apple services — is interfering with security. Fixing it isn’t always straightforward, and the fixes vary depending on how deep you want to go, but they usually boil down to uninstalling or disabling Bonjour, or tweaking registry stuff if the problem is especially stubborn.

Some folks find that just uninstalling Bonjour solves the issue. Others might prefer disabling the service without removing it completely — especially if they still need Apple software but don’t want the conflict. And then there’s the super nerdy registry tweak that removes references to mdnsNSP.dll — kind of scary if you’ve never messed with the registry before, so always make a backup first! Sometimes, if system files got corrupted, running the System File Checker (sfc /scannow) or DISM can fix underlying issues that are causing DLLs to get flagged. It’s all about figuring out what part is causing the block — whether it’s due to Windows security or actual system corruption.

How to Fix the “This module is blocked” Error in Windows 11

Fix 1: Completely Uninstall Bonjour (and maybe other Apple stuff)

• Why it helps: Since Bonjour is often the culprit, removing it stops Windows from blocking its DLLs. This is pretty straightforward and works well if Bonjour isn’t actually needed on your machine.
• When to try it: When you get the error right after installing or updating Bonjour or Apple software like iTunes.
• What to expect: The error should go away once Bonjour is gone. Note that some Apple apps like iTunes might reinstall Bonjour during updates, so keep an eye on that.
• How to do it:
  1. Open Windows Settings (Win + I), then go to Apps > Installed apps.
  2. Search for “Bonjour” in the list. If you find it, click and choose Uninstall.
  3. Optional: Also search for and uninstall other Apple software like iTunes or Apple Software Update because they tend to automatically reinstall Bonjour.
  4. After uninstalling, restart your PC just to be sure.

Pro tip: On some machines, Bonjour or Apple software might stubbornly reinstall after reboot, so you might have to do this a couple of times or block updates temporarily. Windows sometimes loves to re-welcome Apple services like a bad ex.

Fix 2: Disable the Bonjour Service Without Uninstalling

• Why it helps: This way, you keep the software but stop the service from loading into the LSA, hopefully dodging the security block.
• When to try it: If you want to keep Bonjour but avoid these security prompts or errors.
• What to expect: Windows won’t load the mdnsNSP.dll into the LSA, and the error should disappear — at least temporarily.
• How to do it:
  1. Press Win + R, type services.msc, and hit Enter.
  2. Find “Bonjour Service” or “mDNSResponder” in the list.
  3. Right-click, choose Properties.
  4. Change Startup type to Disabled. If it’s running, hit Stop.
  5. Click OK and restart your machine for good measure.

Roughly, this method is less invasive than full removal, and some folks report the error vanishing without losing any functionality. Just keep in mind, if you need Bonjour for certain network stuff, this might cause some glitches.

Fix 3: Tweak Registry to Remove mdnsNSP.dll References (Advanced and Risky)

Now, here’s where it gets edgy. Messing with the registry can either fix the problem or turn your PC into a paperweight if you’re not careful. So, definitely back up your registry first (here’s how).

• Why it helps: It completely removes the references to mdnsNSP.dll from the network provider list in the registry, so Windows stops trying to load it altogether.
• When to try it: If uninstalling or disabling the service didn’t work or if the error persists stubbornly even after disabling Bonjour.
• What to expect: The block should go away, but only if you’re comfortable editing the registry. Otherwise, this is probably overkill.
• How to do it:
  1. Open regedit.exe as an administrator (search for it in Start, right-click, run as admin).
  2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\NameSpace_Catalog5.
  3. Look for subkeys named Catalog_Entries or entries mentioning mdnsNSP.dll. Carefully delete these entries.
  4. Close the registry editor, then restart your PC.

This route is for the brave, but it’s the most definitive way to eliminate references to mdnsNSP.dll that might be causing the block.

Fix 4: Run SFC / DISM to Fix Potential System File Corruption

• Why it helps: Sometimes, system files get corrupted or go missing, which can cause DLLs to get flagged or block entirely. Running these tools makes Windows check and repair itself.
• When to try it: If the error started after some system update or weird crashes, or if other fixes didn’t work.
• What to expect: Hopefully, the tools will repair corrupted files, and the error will clear up without further fuss.
• How to do it:
  1. Open Command Prompt as administrator (Win + X, then choose Windows Terminal (Admin) or Command Prompt (Admin)).
  2. Run sfc /scannow. This will take some time, so be patient.
  3. If issues remain, run DISM /Online /Cleanup-Image /RestoreHealth. It’s slower but more thorough.
  4. Reboot once done and check if the error is gone.

Not sure why it works, but if your system’s been flaky, fixing system files sometimes is the only way to go. Windows has a weird way of making basic repairs a chore, so expect some patience here.

Summary

• Uninstall Bonjour and Apple software if you don’t need it.
• Or disable the Bonjour service without removing it.
• For the advanced brave, go for registry tweaks to remove mdnsNSP.dll references.
• If system files seem dodgy, run sfc /scannow and DISM.

Wrap-up

Basically, this error comes down to Windows being extra cautious and blocking what it sees as risky modules. For most, uninstalling Bonjour solves the problem, because Windows considers it a security risk, especially with recent updates. If things get stubborn, registry tweaks and system file repairs are the next options. Just remember, messing with security features can be risky, so don’t go poking around unless you’re comfortable with it. Fingers crossed this helps someone avoid hours of head-scratching!