Teamview not starting (completely) with Windows but is set to do so

I have enabled Teamviewer to start with Windows.

I have this enabled on several PCs and it works well.

On one  PC despite Remote Unattended Access being enabled and Start with Windows being enabled, when the PC is restarted Teamviewer never becomes remotely accessible without user intervention locally.

For example, after a power cycle, a restart after Windows Update, a Remote restart using Team Viewer, I cannot connect from remote machine unless I physically log into that PC and click on Yes under 'User Acocunt Control' panel.

Which somewhat defeats the objective.

Any suggestions at what to look for please?  I can't figure out what may be causing this need.

As mentioned, my other PCs don't exhibit this problem, I can reliably restart any of them and they will become accessible from remote.

Thanks and regards

Tony