Tailscale backend error after tailscale-ipn-setup-1.8.5.exe completion

Have validated this occurence a bunch of time now on Windows 10 Home, Pro, and Windows Server 2019, bare metal and as VM’s.

The current, on 20210603, version of Tailscale for Windows,as downloaded from

which is


is saying it’s completing the install succesfully but leaving the shortcut

C:\users%USERNAME%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Tailscale

pointing to the prior version of

C:\Program Files (x86)\Tailscale IPN\tailscale-ipn.exe

with the newly installed exe also present on the same path, except it’s named

C:\Program Files (x86)\Tailscale IPN\tailscale-ipn-new.exe

Quite consistently.

Fixed the symptom, not the cause.

Screencap of the message, after logging back in.

The installer writes the new version to a different filename, stops the old version, and moves the new into its place. It looks like something has gone wrong in that, likely the step where it exits the old version, and this results in leaving the link in place as you note.

There are a number of things which might be involved:

  • antivirus examining the newly written file right at the point we’re trying to move it?
  • an actual virus, I suppose
  • another user logged in at the same time?