Can’t open Excel attachments in Outlook? This annoying bug is to blame

The cause appears to be the use of non-ASCII characters in file names. Microsoft describes it like so: “Any user may be ...
XDA Developers on MSN

Sorry, the new Outlook app can't open some Excel attachments, says Microsoft

As spotted by Bleeping Computer, Microsoft has published a new service alert related to Outlook. Labelled as issue EX1189359 and titled "Users may be unable to open Excel files attached to email ...
TWCN Tech News

Excel cannot open the file because the file format or extension is not valid

If you cannot open the Excel file from its location, simply open any Excel file and click the File tab. Then, go to Open > Browse and select the file giving error ...
Houston Chronicle

Why Can't I Insert a File in Microsoft Excel?

Along with the formulas, functions, calculations and data you enter into a Microsoft Excel worksheet, the program also accepts files from other programs as insertions into your documents. If you ...