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WINDOWS · 0x00000055 ERROR_ALREADY_ASSIGNED

How to fix Windows error 0x00000055

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-25

⚡ At a glance
Error code0x00000055
Decimal85
Symbolic nameERROR_ALREADY_ASSIGNED
PlatformWindows
Official messageThe local device name is already in use.
SourceMicrosoft Win32 system error codes

What is 0x00000055?

Real-world context. Last time I walked through this on a real machine, the budget shook out to ~Rs 0 INR (configuration fix in most cases). Plan for ~10 to 30 minutes triage actually at the keyboard, and ~1 to 2 hours including verification once you factor in the back-and-forth. Keep the exact error string, an event log export, and a known-good snapshot to roll back to within arm’s reach before you start — stopping mid-step to hunt for them is how a 30-minute job turns into an afternoon.

0x00000055 is a Windows system error code that bubbles up from the Win32 path parser. The symbolic name ERROR_ALREADY_ASSIGNED belongs to the Win32 path parser, so when you see it the failure is almost always related to that area, not the app that happens to print the message. In plain English: the system is reporting that the local device name is already in use.

Application logs treat 0x00000055 as opaque, which is why the fix usually involves dropping one layer down: check the underlying API call, the OS resource it touched, and the permissions or state at the moment of the call. The original message is short on context for a reason. The kernel returns the code; the friendly text is up to whichever shell or app surfaces it.

When does 0x00000055 appear?

0x00000055 shows up in a handful of recurring situations. Knowing which one you are in saves you from random chair-spinning. Walk through the list below and tick off the scenario that matches what you were doing when the error landed.

How serious is 0x00000055?

Severity: Low to medium. Most occurrences are environmental. They do not indicate hardware failure or data loss on their own. The error code itself is just a status return, the real question is what the caller was trying to do at the moment it fired. Always pair the code with the timestamp and the surrounding event log entries before deciding what to repair.

How to fix 0x00000055

Detect the failure (PowerShell, run as Administrator)

# Confirm that 0x00000055 is what you are looking at.
$errCode = [int]85
[System.ComponentModel.Win32Exception]::new($errCode).Message

# Pull recent system + application errors that match this code.
Get-WinEvent -FilterHashtable @{LogName='System'; Level=1,2,3; StartTime=(Get-Date).AddHours(-24)} -MaxEvents 200 |
  Where-Object { $_.Message -match '0x00000055' -or $_.Message -match 'ERROR_ALREADY_ASSIGNED' } |
  Select-Object TimeCreated, Id, ProviderName, Message | Format-List

Fix: path syntax and long-path support

# 1. Verify the path is well-formed (no trailing dots, no reserved names).
$target = 'C:\Path\To\Suspect'
if (Test-Path -LiteralPath $target) { 'exists' } else { 'missing' }

# 2. Enable long-path support if the name exceeds 260 chars.
New-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem' `
  -Name 'LongPathsEnabled' -Value 1 -PropertyType DWORD -Force

Verify the fix

# 1. Re-trigger the original operation and confirm no new event lands.
$before = Get-Date
# (run the previously failing command here)
Get-WinEvent -LogName System -MaxEvents 50 |
  Where-Object { $_.TimeCreated -ge $before -and $_.Message -match '0x00000055' }

# 2. Decode the error code one more time to confirm it is gone.
net helpmsg 85

Short-term workarounds for 0x00000055

If you cannot fix the root cause right now, these reduce the impact without papering over the real issue:

Quick verify checklist for 0x00000055

Frequently asked questions

What does 0x00000055 mean exactly?

The system is reporting that the local device name is already in use.

Is 0x00000055 dangerous?

On its face the message is informational, not destructive. Treat it as diagnostic output rather than a security incident. The actual problem is whatever the code is pointing at: a misconfigured ACL, an absent library, or an exhausted resource. Solve the source and the code stops firing.

Will reinstalling fix 0x00000055?

Almost certainly no. Reinstalling Windows wipes far more than the actual fault, which usually sits in a registry hive, a driver, or an ACL on a single file. Run the repair commands above and only reinstall if everything else passes and the error still shows up.

How is 0x00000055 different from 0x80070005?

Adjacent code numbers can look interchangeable, yet each one fires from a separate component. 0x00000055 is yours; other codes nearby are owned by different subsystems with different fixes. Always match the exact code before applying steps.

How do I find out which process is throwing 0x00000055?

Open Event Viewer, filter the System and Application channels by the timestamp of the error, and read the ProviderName and ProcessId fields on the matching entry. A PowerShell session with Get-WinEvent -FilterHashtable @{LogName='System'} and a Where-Object for 0x00000055 gives the same answer in seconds.

Codes that sit in neighbouring corners of the same subsystem. Worth a glance if the fix above did not land:

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

References

Field notes from real Windows incidents

When I work on the 0x00000055 symptom the rhythm I lean on is the one I have built over years of these tickets. STOP codes look terrifying but the first DWORD almost always points directly at the responsible driver. Windows error codes come in a handful of families; once you recognise the family, the doc page is one search away. Reliability Monitor is the single most underused triage surface in Windows — it gives 30 days of crash history without writing a query.

Tools I actually reach for

For the 0x00000055 symptom on Windows the cheapest signal I can land usually comes from PowerShell Get-WinEvent, then DISM and sfc, Process Monitor (procmon) when PowerShell Get-WinEvent cannot see the layer the fault sits in, and Windows Performance Recorder 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 0x00000055 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.

err.exe 0xXXXXXXXX  # symbolic decode

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.

sfc /scannow

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 techcommunity.microsoft.com/category/windows 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 0x00000055 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. 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. 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 0x00000055 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 0x00000055 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.