I've been working with Office 2016 almost ever since it was released and very happy with it, in general. My PC (Windows 10 64-bit) is always on, and Outlook is always open. The PC itself is very strong, with 16GB of RAM and SSD disks.
Recently I've noticed that after a while (~1-2 hours) that the Outlook was open and running, it becomes very slow. The switch between message is very slow, even when I open a new message and want to attach a file, for example, it takes quite some time to get the files explorer, and even working inside of it (browsing in the folders and so on). When I shut down Outlook and open it again right away, everything is back to normal, until the next time it turns slow like that.
Now, I'm not sure it's related, but it started happening around the time I switched my free AVG anti-virus software to a PAID ESET Internet Security software. Because this is a paid version, I do not want to just throw it away, and anyway it doesn't guarantee that this is the source of the problem. Moreover, I don't have a general issue of the PC running slow. Everything else in my Windows seems to be running just fine.
Yesterday, I also switched between Office 2016 and Office 365 and the situation is just the same. So it looks like it's something related only to Office, and I'm not sure it's because of the ESET software...
Any suggestions on how to tackle and resolve this will be greatly appreciated.