How to disable LM and NTLMv1 authentication on DHCP

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

Why this matters

Disable lm and ntlmv1 authentication on a DHCP device is one of the highest-volume how-to searches for the Windows Pro Enterprise category. Most users find the menu path inconsistent across DHCP model revisions, so this guide gives a generalised path plus model-specific notes.

Pre-requisites

• A DHCP device that's powered on and on the latest stable service version / OS.
• The DHCP companion app or management tool installed and signed in.
• 5-15 minutes uninterrupted.

Step-by-step

1. Locate the setting. Open settings on your DHCP device. For "disable LM and NTLMv1 authentication", the option lives under one of: General, Advanced, Connectivity, Accessibility, or a DHCP-specific menu. Check the DHCP user manual for your exact model if you can't find it.
2. Toggle the feature on. Confirm the on-screen prompt.
3. Configure sub-options. Most features have 2-3 sub-options (mode, schedule, paired device). Pick values that match your real-world usage pattern.
4. Save / apply. Some DHCP models auto-save, others require an explicit Done / Save tap.
5. Test live. Trigger the feature in a real scenario to confirm the configuration is correct.

Tips that save time

• Pair this feature with a DHCP automation / routine if the device supports it.
• If the feature relies on cloud sync, give it 1-2 minutes after enabling to propagate.
• For multi-user households / multi-admin teams, set per-user profiles so each user sees their preferred state.

Common gotchas

• Feature greyed out. usually service version too old. Update + retry.
• Feature works once then stops, battery saver / power saver mode is killing the DHCP app process. Whitelist it.
• Feature works but with delay: usually cloud-sync latency; check internet speed and DHCP service status.

Region / variant notes

Some DHCP features are region-locked or only available on higher-tier SKUs. If your variant doesn't show "disable LM and NTLMv1 authentication" at all, check the DHCP model spec sheet to confirm support.

Frequently asked questions

How long should the recovery / setup take?

For most DHCP Windows Pro Enterprise cases, allow 15-45 minutes the first time. Repeats are usually under 10 minutes once you know the menu path.

Will this exact procedure work on every DHCP model?

The procedure reflects current DHCP behaviour. Menu paths shift between service version generations; verify against the manual for your specific model + revision.

Is the procedure safe in production / live use?

Apply during a maintenance window where possible. Capture pre-change state. DHCP doesn't usually publish rollback procedures, so make sure you can restore manually.

Does this affect my DHCP support coverage?

Standard operation per the user manual + applying official service version updates does NOT void support coverage. Opening managed services, third-party repair, or unauthorised modifications can void support coverage, check before going further.

Related guides

• All Windows Pro Enterprise guides → /microsoft/section/windows_pro_enterprise.html
• All Microsoft guides → /microsoft/

Related fixes

Related guides worth a look while you sort this one out:

• How to disable LM and NTLMv1 authentication on Active Directory
• How to disable LM and NTLMv1 authentication on BitLocker (managed)
• How to disable LM and NTLMv1 authentication on Defender for Endpoint
• How to disable LM and NTLMv1 authentication on DFS
• How to disable LM and NTLMv1 authentication on DNS
• How to disable LM and NTLMv1 authentication on Failover Clustering

References

• DHCP official support portal for your model.
• DHCP community forum + Reddit threads.
• Vendor PSIRT / advisory page (where applicable).

Reference material, not professional advice. Validate with your vendor manual and follow local regulations.

What changed recently?

Fault diagnosis on the affected device goes faster when you map the symptom to a recent change:

• Did service version update in the last 7 days?
• Did the network (router, ISP, VPN) change?
• Was the device moved physically?
• Did paired devices (phone, hub, app) update?
• Were any accessories swapped in or out?

The answer narrows the root cause to a manageable subset.

Safety + preconditions

Before any work on the device in front of you:

• Unplug from mains for any internal-access procedure.
• flush cached state (circuit breakers in PSUs, residual battery charge) per manufacturer guidance.
• Use ESD-safe handling for boards and modules. no carpet, no wool sleeves.
• Avoid moisture; never apply liquids near vents or connectors.
• If you smell smoke, see scorch marks, or feel uneven heat, stop and escalate.

Verification checklist

After applying the fix on the device, confirm:

• The original symptom is no longer reproducible.
• Related features (status service health indicators, app sync, paired accessories) still work.
• The device responds to a soft reboot without the fault returning.
• Any error codes that were on display have cleared.
• Documentation (your service log, the brand companion app) reflects the change.

When to call How support instead

Escalate if:

• The same symptom returns within 24 hours of a clean fix.
• You see physical damage (burn marks, swollen battery, cracked PCB).
• The device is in support coverage and a hardware replacement is the cheaper outcome.
• Repair requires specialised tools you don't own (alignment jigs, calibration software).
• Following the official path keeps the support coverage intact, which matters more than the time spent.

More frequently asked questions

Why is this happening on a brand-new unit?

Out-of-box defects do occur. If you've owned the device under 30 days and the symptom persists after a tenant reset, escalate to the seller for replacement under DOA terms before opening a manufacturer support case.

What if my model isn't exactly the same revision?

Cross-check the model code on the rating plate against the manufacturer support page. Major service version generations sometimes shift the menu path; the option is usually under a similarly-named section.

What if the fix returns after a reboot?

Persistent fault returns mean either: a hardware fault (escalate), a configuration that's being overwritten by a sync source (check cloud profiles), or a regression in a recent service version update (rollback).

How long does this fix usually take?

Most users complete the steps in 20-45 minutes the first time, and 5-10 minutes on subsequent runs once the menu paths are familiar.

Will this void my support coverage?

Applying official service version updates and following the user manual will not affect support coverage. Opening managed services, jumping safety circuits, or using third-party parts can void support coverage in most jurisdictions.

Field notes from real Windows Pro Enterprise incidents

When I work on disable LM and NTLMv1 authentication on DHCP the rhythm I lean on is the one I have built over years of these tickets. DISM and sfc in that order; doing it the other way wastes a reboot when the component store is the actual problem. Reliability Monitor is the most underused tool in Windows, open it once and you have the last 30 days of crash history without writing a single query. Whenever a Pro/Enterprise box behaves weirdly after a feature update, I check gpresult before I touch anything else: group policy is usually the culprit, not the OS.

Tools I actually reach for

For disable LM and NTLMv1 authentication on DHCP on DHCP the cheapest signal I can land usually comes from rsop.msc, then sfc /scannow, Windows Update Troubleshooter when rsop.msc cannot see the layer the fault sits in, and PowerShell Get-WinEvent for the cases where neither of those answers cleanly. That ordering is not academic. It matches the layers the failure tends to surface through, so the cheap signal lands first and the heavier tooling only comes out when the simpler answer does not hold up under scrutiny.

Verification I run before I close the ticket

Before I mark disable LM and NTLMv1 authentication on DHCP resolved on a DHCP unit, the verification loop below is what I actually run. Each step proves a different layer is green, and the order matters - the cheap checks gate the more expensive ones.

sfc /scannow

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 10

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

Get-WinEvent -FilterHashtable @{LogName='System'; Level=2; StartTime=(Get-Date).AddHours(-24)}

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

gpresult /scope:computer /v

Only when every line above runs clean do I close the ticket and update the runbook with the timestamps.

Where I check first when the docs disagree

When two sources contradict each other on a Windows Pro Enterprise detail, the disambiguation order I lean on is stable. I usually start at learn.microsoft.com/windows for the ground-truth view on Windows Pro Enterprise. I usually start at docs.microsoft.com/windows-server for the ground-truth view on Windows Pro Enterprise. I usually start at support.microsoft.com for the ground-truth view on Windows Pro Enterprise. Random blog posts and reseller wikis are signal, not ground truth, and I treat them as such until the references above either confirm or contradict the claim.

Pitfalls I have walked into on this exact path

The shortcuts that look smart on disable LM and NTLMv1 authentication on DHCP have a habit of biting back. The pitfalls below are the ones I have personally walked into on a DHCP unit, not things I read about. Reliability Monitor is the most underused tool in Windows, open it once and you have the last 30 days of crash history without writing a single query. DISM and sfc in that order; doing it the other way wastes a reboot when the component store is the actual problem. Whenever a Pro/Enterprise box behaves weirdly after a feature update, I check gpresult before I touch anything else. group policy is usually the culprit, not the OS. When in doubt I revert to the slower path that the manual prescribes - the time I save by skipping it is always smaller than the time I spend cleaning up afterwards.

What I tell the next on-call

When I hand disable LM and NTLMv1 authentication on DHCP off to the next person on rotation, the three lines I leave in the runbook are these. First, the symptom signature for DHCP on the Windows Pro Enterprise family - not a paraphrase, the exact string that surfaces. Second, the diagnostic that gave the highest signal in the least time. Third, the exact verification command whose green output justified closing the ticket. That trio is what turns a one-off fix into a runbook entry the next engineer can use without paging me at three in the morning.

I also add a one-line note on the cost of getting this wrong. For disable LM and NTLMv1 authentication on DHCP on a DHCP unit, the cost is rarely the replacement part. It is the downtime, the second site visit, and the trust deficit you spend with whoever owns the asset when the fix does not hold. That framing keeps the next on-call from choosing the cheap-looking shortcut that ends up costing the most in elapsed hours and goodwill.