All of the sudden users are unable to open reports exported from Salesforce with Excel. We are running insider slow (targeted release) and have been from the beginning. Looks like a new update came through last night, which I am guessing is the problem. We redirect to OneDrive for desktops,documents, and downloads. If the file is copied to another local drive folder, they open. Otherwise, Excel opens but with no file. These are XLS files but they appear to be in some form of HTML Excel formatting. Previously users would be prompted that the file format and extension do not match. This prompt no longer occurs. Any Salesforce folks out there able to duplicate?