I have found the culprit!.
I run Malewarebytes Antimaleware 18.104.22.1680 as a resident program as one of the programs that load at startup.
After disabling all programs I uninstalled Boxcryptor v22.214.171.124, rebooted and installed 1.3. The program worked as expected. I then decided to load each of my startups one at a time to see what happened. By chance MAB was the first program I tried. Boxcryptor 1.3 would not lock as before. The log file was as follows:
13:55:2415 | Operating System: Microsoft Windows NT 6.1.7600.0
13:55:2571 | .NET version: 3.5.30729.4926
13:55:2571 | BoxCryptor v126.96.36.199 started!
13:55:7556 | Mounting...
13:55:7556 | Creating Storage...
That is all that happened for 40 min.
If I the reboot with the MAB service program disabled 1.3 functions normally.
As I use the same startup programs at home as here at work I think this is the answer.