Why does the mail app opens unexpectedly while using other apps, for example the preview app

Okay, Old Toad. You may have solved the issue I described. It has been 3 since I followed your advise and have not seen the mail app open on it own. The little notice of new mail or messages show up in the top right of the screen but that doesn't bother me.

Thank you for your help.

Luis, I thought that the first time it happened. I am very aware of the possibility, however I was confident that I had not done that. With the 2nd occurrence I was sure that was not the case. The most recent occurrence I was viewing a photo and did not even have a hand on or near the keyboard or trackpad.

Thank you for your reply.

I appreciate the response. So far I am not certain that my iMac rebooted into safe mode. I followed your instructions a three times but don't believe it ever reached safe mode (because there was no delay in the starting process as described). I did open and close Preview several times. I am now in normal start up and will report back regarding the issue. It may be a day or two.

Thanks for your reply

Well, today the mail app opened while I was viewing a Safari window. No hands on keyboard or track pad at the time.

Yes, I do have a google mail account but no calendar account.