A SharePoint file is downloaded instead of opening the Office application with a direct connection to it
This article was written by Warren Rath, Support Escalation Engineer.
Assume that you have Microsoft Offices Online in a SharePoint farm. When you open a URL (like http://sharepointserver/Shared%20Documents/DateTest.docx) to a SharePoint document by using the Chrome browser, the document is downloaded directly instead of opening the Office application with a direct connection to the document on SharePoint.
This is how the Chrome browser works.
To resolve this issue, add "?web=1" to the end of the URL, and then the document will be opened in the Chrome browser.
For example, http://sharepointserver/Shared%20Documents/DateTest.docx?web=1