Ouch! That is bad! I can see you may want to go back to Outlook 2007.
Well, the problem is two-fold. First, the real cause of the issue was the corruption of the PST file. That was caused by repeated importing of e-mails from the server (think 13,000 messages repeatedly loaded). That drove the size of the PST file past what Outlook 2007 could handle. The file got corrupted. Attempts to repair it were cumbersome, time-consuming, and ultimately successful. However, there were casualties - like the calendar. Calendars and e-mail messages are kept in separate PST files. I didn't even know the calendar PST was damaged. Anyway, my entries for the next 3 months (maybe longer) are just gone. I've got e-mails for things in 1969 (didn't know about them ) and a reminder to file my PA taxes in 2743!
Second, Outlook 2016 just seems to be very slow. A video I just saw comparing 2010 and 2016 shows that significantly larger amounts of resources are consumed by 2016. Wish I'd seen that on Monday.
The bottom line is that the damage has been done. Even if I de-install Outlook 2016, I really need to shrink the PST file and update the calendar. My hope is that performance will improve. If not, then I need to pray that a reversion to Outlook 2007 will go smoothly and yield a running e-mail system. It's a tough call.
And all of this is really keeping me from doing much, if any, modeling. I really didn't count on doing my IT support in my retirement.
OK, I'm done venting now.