loadmatfile load files using the Matlab data format. When you type
save(“variables.mat”)
your current user variables are saved in the Scilab format, regardless of the filename extension. If you need to share data with Matlab use savematfile instead. Since the filebrowser is aware of the extension, if you want to load your Scilab data files with a double click use the legal .sod (Scilab Open Data) extension (see save - Saves some chosen variables in a binary data file)