I'm working with filr 3.2 and excel file in .xls format.
If I open the file with in place editing (from browser or from a mapped disk via WebDAV) I'm able to modify it, but when I save it I receive one error: file not saved.

The same operations on the same file, but in XLSX format are fine: I'm able to open it an save it without any errors.

Some one can explain me why?