Be aware of the behavior that the [Open in Excel] button is displaying in grayout state via Google Chrome.
I am aware of the behavior that the [Open in Excel] button is displayed in a grayout state when opening the Excel file with the password via Google Chrome browser after updationg the Google Chrome browser on 22June . Please see below the screen shot file attached. I would say if I selected a file from OneDrive for Business and open it on Excel Online, the user can open the file. However, since SharePoint sites are linked to OneDrive for Business files, we must display them in Excel Online and click [Open in Exce] buttonl.
I think that it is a problem on the Google Chrome side, but if Microsoft can deal with anything for this problem, please make sure the [Open in Excel] will be working correctly via Google Chrome. We are using Google Chrome browser in our internal operation. Thanks.