[Windows Client] Joining a Twingate network fails with "Unable to join network"

Last updated: September 21, 2026

Symptoms

  • On a Windows operating system, joining the Twingate network fails

  • Twingate.log (%LOCALAPPDATA%\Twingate\logs) shows:

[ERROR] [client] Preconnection check failed. TapAdapterExistence details: Twingate [ClientPreconnectionChecksRunner.CallService]

  • Twingate.Service.log (%PROGRAMDATA%\Twingate\logs) shows:

[ERROR] [client] Preconnection check failed. [ConnectionService.RunPreconnectionChecks] Twingate.Client.Common.PreconnectionChecks.Exceptions.PreconnectionException: Twingate adapter is missing from the computer
   at Twingate.Client.Common.PreconnectionChecks.TapAdapterExistenceCheck.ExecuteAsync()
   at Twingate.Client.Common.PreconnectionChecks.PreconnectionChecksRunner.Start(PreconnectionConfig config)
   at Twingate.Client.WinService.Connection.ConnectionService.<>c__DisplayClass33_0.<<RunPreconnectionChecks>b__1>d.MoveNext()

Cause

The Twingate service cannot locate a usable TAP adaptor. Any of the following will produce it:

  • The adaptor is disabled

  • The adaptor is absent

  • The adaptor's FriendlyName has been changed from Twingate TAP-Windows Adapter V9

The third is commonly reported on machines where other TAP-based software is, or was previously, installed OpenVPN and FortiClient among them. Two things make this easy to miss:

  • The names are near-identical. OpenVPN's adaptor is TAP-Windows Adapter V9; ours is Twingate TAP-Windows Adapter V9. Compare the full string rather than scanning for "TAP-Windows Adapter V9".

  • Removing the other software does not necessarily restore the name. This can present on a machine with no other VPN currently installed and no other TAP adaptor visible.

Resolution

Work through these in order. Only use the registry step if the first two don't resolve it.

1. Check the adaptor exists and is enabled

Control Panel > Network and Internet > Network and Sharing Center > Change adapter settings. If the Twingate adaptor is greyed out, right-click > Enable and retry the connection. Or:

powershell

Get-NetAdapter | Where-Object InterfaceDescription -like '*Twingate*' |
  Select-Object Name, InterfaceDescription, Status

2. Check the adaptor's name

powershell

Get-ItemProperty 'HKLM:\SYSTEM\CurrentControlSet\Enum\ROOT\NET\*' |
  Select-Object PSChildName, FriendlyName, DeviceDesc

FriendlyName should read Twingate TAP-Windows Adapter V9 exactly. Note the PSChildName of that entry it is the key index used below, and it is not always 0000.

3. Correct the name

  • If another VPN is still installed and no longer needed, uninstall it as cleanly as possible first

  • Back up the key before editing:

  reg export "HKLM\SYSTEM\CurrentControlSet\Enum\ROOT\NET\0000" tap-backup.reg

  • Set FriendlyName to Twingate TAP-Windows Adapter V9, substituting the index from step 2

  • Reboot

4. If the failure persists

Reinstall the Twingate Client. If that doesn't resolve it, contact support with both log files.