Is my document uploaded?

No. The file is opened and converted inside your browser. It is never sent to a server.

Can it open old .doc or .xls files?

No. Only the modern formats (.docx and .xlsx) are supported. Open the file in an office application and save it in the newer format first.

No. Each cell shows the result that was saved in the file the last time it was calculated.

Hiding a sheet in Excel does not protect it. Its contents are stored in the file like any other sheet, so they are shown and labelled as hidden.

JavaScript is turned off. InspireTools processes files in your browser, so the tools need JavaScript to run.

Open .xlsx workbooks in your browser without Excel.