This issue arises with FileZilla possibly due to lack of native support for the XLSX file extension. The fix is to manually map the associations for Excel in FileZilla (you may not need both, but I included xls for good measure):
- In FileZilla goto Settings, then File Editing / File Type Associations
- In the Custom filetype associations pane, enter in the following:
- xls “C:\Program Files (x86)\Microsoft Office\root\Office16\EXCEL.EXE”
xlsx “C:\Program Files (x86)\Microsoft Office\root\Office16\EXCEL.EXE”
- xls “C:\Program Files (x86)\Microsoft Office\root\Office16\EXCEL.EXE”
Obviously you will need to use your own path for Office and the excel executable.
The same process would apply if you noticed trouble with the DOCX file extension or any other filetype you are trying to VIEW/EDIT from FileZilla.