HEALTH HAZARD 1
Having used Outlook previously for my Calendar, Contacts, and email, I figured I would use Outlook 2016, which comes with Office 365. After starting Outlook 2016 and syncing my iPhone and iPad with iTunes, I noticed that there were no contacts and no appointments on either. They also vanished from Outlook 2016. ALL GONE!!! I almost had a heart attack.
I called Apple, figuring that the problem might be iTunes. Perhaps it was, I will never know, because Apple blamed it on Microsoft and said to call Microsoft. That despite the fact that the iTunes sync blew the data on Apple devices. Oh well.
I called Microsoft. They blamed it on Apple. However, the support person, located in India, knew something about Apple and, after an hour or so, I was set up on Apple's iCloud with all my Apple devices synced and Outlook 2016 synced to the iCloud data. However, iTunes still won't talk with Outlook 2016 to sync my contacts with my Apple devices or iCloud.
HEALTH HAZARD 2
Window 10 is that it updates automatically - you don't even know it is happening. No doubt, Microsoft figured that this is a great plus, since people who don't know much about computers don't have to. However, what Microsoft fails to tell you is that during an update, or before restarting the computer when that is required to finalize the update, it can appear that you have experienced a serious computer problem.
Today, I was using Office 365, and Outlook 2016 in particular. At one point, I closed Outlook 2016 and my other open programs, and backed up my documents using Norton 360. When I went to reopen Outlook 2016, I received a message saying that Outlook couldn't be opened because such and such a file couldn't be opened. The file was the primary Outlook file that stores, you guessed it, my email, appointment, and contacts data. ALL GONE AGAIN???? I almost had a heart attack.
What does one do in such a situation, Reboot and hope for the best. It worked. And at that point, the tiny little "notifications" icon indicated that there was a message waiting. It said that a reboot was necessary to finish updating Windows 10. Evidently, the update program had waited to modify Outlook until I wasn't using it, and then blocked access to the key file until a reboot had completed the update.