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Free Fix 0x00000001

Avira error 0x00000001 and 501: install and update failures on Windows

11 min read Updated October 4, 2026 Antivirus & Endpoint Security

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0x00000001 is a bare failure value of 1: setup or the updater reports that a step failed without saying which. Two of the companion numbers do carry published meanings, and they are Windows Installer patch errors rather than general setup errors, which changes where you look.

Run in an elevated Command Prompt if setup fails at a different point each time, then restart

sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth
  1. Delete the installer you have and download a fresh copy from Avira, then right-click it and choose Run as administrator.
  2. Check the things Avira lists as prerequisites before anything else: system requirements met, no competing antivirus installed, current Windows updates, and .NET Framework 4 present.
  3. If setup still fails, uninstall Avira from Settings, Apps so the Avira Uninstall Wizard runs, and restart.
  4. If the uninstall will not complete, follow Avira’s manual reinstallation procedure: boot into Safe Mode and delete C:\Program Files\Avira and C:\ProgramData\Avira, then restart.
  5. Install from the fresh installer with no other security product mid-installation, then let the product complete its first update before judging whether it worked.

If the number you have is 1650 or 1651, stop and read the Windows Installer section below. Both are patch errors, and neither is fixed by clearing leftovers.

If setup completes and the first update runs, you are done. If not, the next section separates a broken installation from a blocked update path, which are different problems that share these numbers.

Why it happens

An antivirus install is not a file copy. Setup writes program files, registers services, installs drivers that let the scanner see file activity as it happens, and creates data folders it will later write into. Any of those can be refused: by insufficient rights, by a file locked by a service that is still running, by another security product defending its position, or by a folder whose permissions were left behind by an earlier install.

The installer reports only that a step failed. 0x00000001 is literally the number one, and 501 is in the same category: an internal identifier for a failure, not a diagnosis. Avira publishes no meaning for either, which is why searching the number alone produces so much contradictory advice. The productive approach is to remove variables in order rather than to look the number up.

1650 and 1651 are different, because they are not Avira’s numbers at all. Both are Windows Installer errors with published meanings. 1650 is ERROR_INVALID_PATCH_XML, the XML patch data is invalid. 1651 is ERROR_PATCH_MANAGED_ADVERTISED_PRODUCT, an administrative user failing to apply a patch to a per-user managed or per-machine application that is in the advertised state. Both are about patching an existing installation, not about a fresh install, and both point at the state of the installed product and at how it was deployed.

Update failures deserve a separate thought from install failures. A product that installs cleanly and then cannot update usually has a path problem rather than an installation problem: a system-level proxy that was never configured, an appliance inspecting TLS, or a clock wrong enough that certificate validation fails. Those surface during the update stage, and no amount of reinstalling moves them.

Remains of a previous installation are blocking setup

You have this one if You have installed, upgraded or removed Avira on this machine before, and the failure repeats at exactly the same point.

  1. Uninstall from Settings, Apps so the Avira Uninstall Wizard runs, and restart.
  2. If that will not complete, use Avira’s manual procedure: Safe Mode, then delete C:\Program Files\Avira and C:\ProgramData\Avira.
  3. Confirm no Avira service remains in services.msc before reinstalling.
  4. Install from a freshly downloaded installer, run as administrator.

Avira publishes no dedicated removal or registry-cleaning utility for Windows. Anything presented as one from a third-party download site is not the vendor’s tool and should not be run on a machine you care about.

A patch is being refused rather than an install failing

You have this one if 1650 or 1651 rather than a bare failure value, usually while updating an installation that is already there.

  1. For 1650, treat the patch itself as unusable: get a fresh installer from Avira rather than reapplying the same update.
  2. For 1651, check how the product was deployed. The error names a per-user managed or per-machine application in the advertised state, which is a managed-deployment condition rather than a consumer one.
  3. On a managed machine, take it to whoever owns the deployment. Reinstalling under a different account will not change the product’s advertised state.
  4. Where the machine is not managed, remove the product cleanly and install fresh instead of patching.

Setup is not running with full rights

You have this one if Setup dies early, or rolls back before it reaches the driver stage.

  1. Sign in with an account that is a local administrator.
  2. Right-click the installer and choose Run as administrator explicitly.
  3. If installs are restricted by policy, ask for an exception rather than fighting the installer.
  4. Try again and note whether the failure point moves.

Another security product is defending its position

You have this one if Setup fails at the driver or service stage, and the other product’s quarantine or log mentions an Avira file.

  1. Pause the other product’s real-time protection for the duration of the install.
  2. Check its quarantine and restore anything of Avira’s it has taken.
  3. Install, then re-enable the other product’s protection immediately.
  4. Decide whether you actually intend to run both, and remove one properly if not.

Avira lists a conflicting antivirus as one of its four documented causes of a failed installation, alongside unmet system requirements, missing Windows updates or .NET Framework 4, and remains of an earlier Avira install.

Windows Installer or the temp folder is unhealthy

You have this one if Other software also fails to install, or setup complains it cannot write to a temporary location.

  1. Check free space on the system drive; installers need room beyond the size of the finished product.
  2. Clear the user temp folder: press Windows and R, type %temp%, and delete what will delete.
  3. Run sfc /scannow then DISM /Online /Cleanup-Image /RestoreHealth elevated, and restart.
  4. Install again and read the new result rather than assuming the old number still applies.

Full reference

Where in the process it fails

When it fails Most likely cause
Immediately on launching setup Rights, or a damaged or truncated download
At the same point every attempt A specific file or registry write is blocked, usually by leftovers
At a different point each attempt Disk space, the temp folder, or Windows Installer health
Setup completes but the first update fails The update path out of the machine, not the installation
Only where another suite is installed The other product is blocking driver or service registration
1650 or 1651 during an update A Windows Installer patch refusal, not an Avira fault

The two numbers that do have published meanings

Code Symbolic name What Microsoft publishes
1650 ERROR_INVALID_PATCH_XML The XML patch data is invalid
1651 ERROR_PATCH_MANAGED_ADVERTISED_PRODUCT An administrative user failed to apply a patch for a per-user managed or per-machine application that is in the advertised state

Both belong to Windows Installer rather than to Avira, and both concern patching an installation that already exists. That matters because the standard advice for a failed antivirus install, remove the leftovers and try again, is the wrong shape for either of them. 1650 says the update package cannot be read; get a different one. 1651 says the product is in a deployment state that blocks the patch; the answer is with whoever deployed it, or a clean removal and a fresh install.

Avira’s own documented uninstall route

  1. Open Settings, then Apps, find the Avira product and choose Uninstall. Avira documents this as opening its Uninstall Wizard.
  2. Where the conventional removal is not possible, Avira publishes a manual reinstallation procedure instead.
  3. That procedure boots Windows into Safe Mode, shows hidden files, and deletes C:\Program Files\Avira and C:\ProgramData\Avira.
  4. On Windows 7 only it also runs netsh winsock reset from an elevated Command Prompt, followed by a restart.
  5. Then install again from a freshly downloaded installer.

The manual procedure deletes the product’s data folder along with the program folder, which takes settings, exclusions and anything in quarantine with it. Restore anything you still need out of quarantine first, and note which Avira account the licence belongs to before you start, purely so you are not hunting for it afterwards.

When the install works and the update does not

  • Check the clock and time zone. Certificate validation fails on a badly wrong date, and the failure looks nothing like a clock problem.
  • Test on a different network. An install that updates on a phone hotspot and not in the office is a gateway question, not an endpoint one.
  • Check for a TLS-inspecting proxy. A substituted certificate breaks the download without producing a proxy-shaped error.
  • Confirm the product finished its first update at all. A fresh installation with no data is not the same as a working one.

Knowing when to stop

If two clean attempts fail on a machine where the prerequisites are met and no other security product is installed, the fault is more likely to be in the Windows image than in the Avira package. At that point sfc /scannow and a DISM restore health pass are worth more than a third reinstall, and if those find and repair something, retry before doing anything else. Microsoft Defender is a legitimate place to stop as well: it needs no installation, costs nothing, and does not care what state the Avira package is in.

Every code this article covers

Code What it points at Source
0x00000001 A bare failure value of 1 returned by setup or the updater. It records that a step failed, not which one not published by the vendor
501 Another internal setup or update failure identifier. Avira publishes no meaning, and the fix does not depend on the number not published by the vendor
1650 ERROR_INVALID_PATCH_XML: the XML patch data is invalid. A Windows Installer patch error, not a general setup failure Microsoft Learn
1651 ERROR_PATCH_MANAGED_ADVERTISED_PRODUCT: an administrative user failed to apply a patch for a per-user managed or per-machine application in the advertised state Microsoft Learn

Confirm the fix worked

  1. Setup completes and offers to open the product rather than rolling back.
  2. The product opens, reports its licence state, and completes an update without error.
  3. Its services show as running in services.msc after a restart.
  4. A scan runs to completion and writes a result you can open in the product’s own report view.
  5. Windows Security, Virus & threat protection, Manage providers lists one antivirus rather than two.

Questions people ask about this

Does this cost anything to fix?

No. This is a broken installation, not a licensing problem, and every step uses the vendor’s own instructions or facilities already in Windows. Your entitlement is untouched by a reinstall.

Will I lose my licence by removing the product?

No, provided you know which Avira account it belongs to. The entitlement is held by Avira against the account, not inside the installation, and Avira documents the licence being recognised automatically once you reinstall and sign in.

Where is Avira’s removal tool?

There is not one in Avira’s current documentation for Windows. The documented routes are the Uninstall Wizard from Settings, Apps, and, where that fails, a manual procedure in Safe Mode that deletes the Avira program and data folders. Do not download something described as an Avira cleaner from a third-party site.

What do 0x00000001 and 501 actually mean?

Nothing published. They are internal identifiers for a failed step. Any page that assigns a specific cause to either is guessing, and the guess does not change what you do: check rights, leftovers, competing products and Windows Installer health, in that order.

Should I install a different antivirus instead?

That is a reasonable question rather than a defeat. Microsoft Defender is built into Windows, needs no installation and costs nothing. If Avira will not install cleanly and you do not need a specific feature of it, Defender is a legitimate place to stop.

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