For certain particular .mat files that I have, it takes "whos -file" a really long time (~10 sec) to give me the summary of the contents of the file. Also, when I highlight the file in the Current Folder window, the pane which is supposed to show the file contents appears empty, even though "whos -file" tells me otherwise. It remains that way no matter how long I wait.
Admittedly, these .mat files contain large data (~1 GB), but should that matter? Isn't the WHOS summary info contained in headers, and therefore shouldn't extracting this info be easy, quick, and reliable?