Recently a user of 365 Sharepoint could not open a file via Excel from Internet Explorer Sharepoint Site. The error below came up

Microsoft Excel cannot access the file “…”. There are several possible reasons:

-The file name or path does not exist.

-The file is being used by another program.

-The workbook you are trying to save has the same name as a currently open workbook.

The file could be downloaded and opened , just not streamed from Sharepoint

Removing the spaces in the filenames to – fixed this