Opening a spreadsheet or Word attachment in the mailbox said "No preview available". Office files are now shown through Microsoft's online viewer, the same way committee documents already are, with Download still there if the viewer cannot reach the file.
Above: when an attachment arrives as part of an email there's a preview or download drop down associated with it:
Below: Preview of Excel sheet using the Microsoft Online viewer. Different tabs can be navigated by clicking them at the bottom of the window.
