Doesn't seem anyone is interested in this discussion - but I also have the same problem. The first time I try to open an Excel 2016 file it tells me it is corrupted and cannot be opened. When first opening it only goes to "processing" and then the message. I then close down the resulting blank excel sheet plus a "ghost" sheet Excel creates with nothing there, not even a grid. Then I go and open the file a second time and everything opens ok. This is on any file I try to open.
Eventually sometime during the day Excel then locks up and I have to shut Excel down and start again. Its very annoying, but doesn't seem to be solvable. Trusted Sites does not solve this.