Cisco VPN Error 27850: Fixing the Uninstall Failure

Fixing Cisco VPN Client Error 27850

Error 27850 on the (legacy) Cisco VPN Client typically shows up when you try to install or uninstall the client and it fails partway through, usually because of leftover configuration from a previous install that Windows Installer can’t cleanly reconcile. The most common and reliable fix is to remove the leftover Cisco Systems VPN Adapter entry from your network adapters before attempting the install or uninstall again:

• Open Device Manager, show hidden devices (View menu), and look under Network adapters for a “Cisco Systems VPN Adapter” — uninstall it if present.
• Check Control Panel > Network Connections for any leftover Cisco VPN adapter entries and remove those too.
• Reboot before attempting the install or uninstall again.

If the error persists after that, Microsoft’s Program Install and Uninstall troubleshooter can often clear a stuck installer registration that’s causing this specific class of error, without you needing to dig through the registry by hand. Worth knowing: the legacy Cisco VPN Client used in this kind of setup has been end-of-life for a long time and doesn’t support modern Windows well. If you have a choice, Cisco’s current AnyConnect Secure Mobility Client is the actively maintained replacement and avoids this class of legacy installer issue entirely.

A Naming Update Worth Knowing (Updated for 2026)

Cisco has since rebranded its VPN client — what this post calls “AnyConnect Secure Mobility Client” is now marketed as Cisco Secure Client (including AnyConnect), with the older AnyConnect name retained only as a parenthetical reference in current documentation rather than as the standalone product name. The advice stands either way: if you’re still fighting Error 27850 on the legacy standalone Cisco VPN Client, moving to the current Secure Client avoids this whole class of installer conflict rather than working around it.

Resources

• Cisco