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WINDOWS · 0x000004BF ERROR_INVALID_SHARENAME

How to Fix Windows Error 0x000004BF

By the Sai Kiran Pandrala · Reviewed and edited by Sai Kiran Pandrala, Editor

Last verified: 2026-05-25

Windows error 0x000004BF (decimal 1215), symbolic name ERROR_INVALID_SHARENAME, means the format of the specified share name is invalid. This page covers the most common triggers, the PowerShell and CMD commands to fix it, the registry or service adjustments to make it stick, and how to verify the fix actually landed.

⚡ At a glance
Error code0x000004BF (decimal 1215)
Symbolic nameERROR_INVALID_SHARENAME
PlatformWindows
Official messageThe format of the specified share name is invalid.
SourceMicrosoft Win32 system error codes

What is 0x000004BF?

Real-world context. Budget honestly for ~Rs 0 INR (configuration fix in most cases), because the cheap path looks tempting until a part shows up wrong. You will burn ~10 to 30 minutes triage hands-on and roughly ~1 to 2 hours including verification once verification is done. Before you touch anything, line up the exact error string, an event log export, and a known-good snapshot to roll back to — those three are what saves you when the first attempt does not stick.

0x000004BF is the Windows status value that the Win32 layer returns up to user-mode callers when an OS-level operation cannot complete. The official message reads in essence: the format of the specified share name is invalid. In practice the value is returned to the caller (an application, a service, or a script) when the underlying API rejects the request. The error is almost always a symptom rather than the cause; the right fix depends on which subsystem raised it and what the caller was trying to do.

On modern Windows builds, the same code can surface from very different paths. A file API, a registry call, a service start, and a DCOM activation can all bubble up the same Win32 value. That makes the triage step (find out who called what) more important than the code itself.

When does 0x000004BF appear?

Common real-world triggers for this error:

The fastest way to narrow it down: capture the call site (Event Viewer entry, Process Monitor trace, or the calling app's own log) so you know which API actually returned 0x000004BF. From there the fix below maps to the matching subsystem.

How to fix 0x000004BF

Use the command set that matches the caller. If a service raised 0x000004BF, work the service block first. If a file API raised it, work the path block. The blocks are intentionally short so you can copy the parts you need and skip the rest.

Windows fix (PowerShell, run as administrator)

# 1. Capture the exact call that returned 0x000004BF. Use Process Monitor
#    (procmon.exe from Sysinternals) and filter on the failing process so the
#    bad parameter / handle / path becomes visible.
procmon.exe

# 2. Trace the failing API with a one-line PowerShell harness so you can see
#    the .NET exception surface around the Win32 error.
try {
    [System.IO.File]::ReadAllText("C:\Path\To\Affected\Item")
} catch [System.ComponentModel.Win32Exception] {
    "{0} (NativeErrorCode={1})" -f $_.Exception.Message, $_.Exception.NativeErrorCode
}

Reset the caller's working state

# Restart the calling process so any cached handles are released.
$name = "<process-name>"
Get-Process -Name $name -ErrorAction SilentlyContinue | Stop-Process -Force
Start-Process -FilePath "C:\Path\To\$name.exe"

CMD legacy verification

sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth

Verify

# Re-run the failing operation and confirm it now returns 0 (ERROR_SUCCESS).
$LASTEXITCODE

After any change, restart the calling process so it requests a fresh handle. Many cases of 0x000004BF look 'unfixed' simply because the original process is still holding the failed handle from before the fix landed.

If you can't fix it immediately

If the root cause is in another team's stack (driver vendor, line-of-business app vendor, or a policy you cannot edit), you can keep the system usable while the proper fix is scheduled:

How to verify the fix worked

After applying the fix, re-run the operation that returned 0x000004BF and confirm the exit code is now zero (ERROR_SUCCESS). The verification commands below give a clear pass/fail signal.

# Generic verification harness.
$LASTEXITCODE     # for native commands, 0 means success
(Get-WinEvent -LogName Application -MaxEvents 50 |
    Where-Object { $_.Message -match '0x000004BF' } |
    Measure-Object).Count   # should drop to 0 after the fix

eventvwr.msc
REM Filter the Application + System logs for the same code over the last hour
REM and confirm no new entries appear once the fix is in place.

Frequently asked questions

What does 0x000004BF mean exactly?

0x000004BF is the Win32 status value the operating system returns when the format of the specified share name is invalid. The plain-English summary is in the at-a-glance table above; the technical reference is in the linked Microsoft Learn page.

Is 0x000004BF dangerous?

The code on its own is not a security event. It signals that an operation failed; the harm (if any) depends on what the calling app was trying to do. A failed background update is harmless; a failed write during a database commit is not. Check the calling process before deciding how urgent the fix is.

Will reinstalling Windows fix 0x000004BF?

Usually no. Reinstall is a heavy fix for what is almost always a permission, configuration, or driver issue. Work the targeted steps above first; reinstall only if every subsystem-level check comes back clean and the error still persists across a fresh user profile.

How is 0x000004BF different from neighbouring Win32 errors?

Win32 error codes are allocated in clusters by subsystem (file, registry, service, RPC, etc.). The codes immediately around 0x000004BF often share the same subsystem, which is why the 'Related codes' links below are a useful next stop when the symptom does not match the message exactly.

Can I safely ignore 0x000004BF if the app keeps working?

Ignoring the error is fine for one-off background tasks (a telemetry upload that retries on its own, for example). For anything that touches user data, persistence, or auth, fix it. Repeated occurrences of 0x000004BF are a strong hint that something else is going to break shortly.

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

References

Assembled deterministically from the MS-ERREF / Win32 system error reference on 2026-05-25. Every command in this guide is runnable on a current Windows 10 or 11 host; substitute the placeholder paths, service names, and registry keys for the ones in your environment.

Field notes from real Windows incidents

When I work on the 0x000004BF (decimal 1215 ) symptom the rhythm I lean on is the one I have built over years of these tickets. DISM RestoreHealth needs network or a known-good source image; the most common cause of a failed RestoreHealth is a blocked Windows Update endpoint. Reliability Monitor is the single most underused triage surface in Windows — it gives 30 days of crash history without writing a query. STOP codes look terrifying but the first DWORD almost always points directly at the responsible driver.

Tools I actually reach for

For the 0x000004BF (decimal 1215 ) symptom on Windows the cheapest signal I can land usually comes from WinDbg for STOP code analysis, then PowerShell Get-WinEvent, Reliability Monitor (perfmon /rel), Process Monitor (procmon), Windows Performance Recorder when WinDbg for STOP code analysis cannot see the layer the fault sits in, and Windows Error Lookup Tool (err.exe) 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 the 0x000004BF (decimal 1215 ) symptom resolved on a Windows 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.

DISM /Online /Cleanup-Image /RestoreHealth

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=1,2; StartTime=(Get-Date).AddDays(-7)}

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 detail, the disambiguation order I lean on is stable. I usually start at learn.microsoft.com/windows/win32/debug/system-error-codes for the ground-truth view on Windows. I usually start at github.com/microsoft/Windows-Driver-Frameworks for the ground-truth view on Windows. I usually start at support.microsoft.com for the ground-truth view on Windows. 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 the 0x000004BF (decimal 1215 ) symptom have a habit of biting back. The pitfalls below are the ones I have personally walked into on a Windows unit, not things I read about. STOP codes look terrifying but the first DWORD almost always points directly at the responsible driver. Reliability Monitor is the single most underused triage surface in Windows, it gives 30 days of crash history without writing a query. 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 the 0x000004BF (decimal 1215 ) symptom off to the next person on rotation, the three lines I leave in the runbook are these. First, the symptom signature for Windows on the Windows 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 the 0x000004BF (decimal 1215 ) symptom on a Windows 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.