In the end it was AVG. Maybe a rootscan at shutdown? Removed and reinstalled with no fix. Had to switch, now running Avira.

Slow shutdown after upgrading to Windows 10 on my T61p

T61p, T9500, SSD

Updated Windows 7 Pro 32 to Windows 10 Pro 32 in place. All works well after a couple of
tweeks. Only tweek I did not...