iTunes opens without window

Yes when you quit itunes use the command Q or from the drop down menu File> Quite.

Command W or the red pill button will only close the Window, not quit the app.

So if you reboot with no open Window, that is what you get, iTunes launches with no open window.

In this instance Command 0 will open the Window.

iTunes - Official Apple Support

From the iTunes>Help>iTunes Help

OmPranava wrote:

Thank You, but since I have my desk / mac in my bedroom I prefer having the least amount of electromagnetic fields around me at night. I guess I will have to keep ⌘0 ing until the bug is fixed :-)

Understood.

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Bug Reporter https://bugreport.apple.com/

OmPranava wrote:

It happens specifically after turning the Mac on again (start or restart), which happens daily as I shut it off over night.

Any other idea?

Yes.

There is no need to shut the mac down at night, there is no advantage. Just close the lid and pickup in the morning where you left off— iTunes will be waiting for you.

Your Machine will be happier not having to load the whole system and all the apps back up.

OmPranava wrote:

Thank You, but since I have my desk / mac in my bedroom I prefer having the least amount of electromagnetic fields around me at night. I guess I will have to keep ⌘0 ing until the bug is fixed :-)

FWIW, what you describe should not happen. It is not a "bug" per se but something is amiss with your install. You can try creating a new user and see if it still occurs.

You should also try while in Safe Mode. If it still occurs in both cases you may need to reinstall.