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
is saying it’s completing the install succesfully but leaving the shortcut
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
Fixed the symptom, not the cause.