iTunes won't open twice without reboot

[Expatriate]

I have the latest version of iTunes. At the moment, I can't open it to get you a version number because I have already had it open this boot of my PC. Once it has been open then closed (File --> Exit) it will not open again until my PC (W10) has been rebooted.

Is this standard practice (SNAFU ) or do I need some different setting?
Thanks

 

[Expatriate]

Hold the phone!
Just out of spite, iTunes opened this time.
It hasn't done that for a month.

I'll keep you posted.