Ok, best I could do was allow you to recover your simulations and post processing but not the models..
I suspect that somehow maybe S4L was saving when the computer crashed or somehow restarted and this corrupted the smash file.
A quick explanation:
Smash files are .h5 files (you can use an hdf viewer - I use HDF Viewer 2.13 - to sort through the data structure). I compared your smash file to another smash file and I noticed that the field "Data -> _Object -> _DocumentVersion" was missing so I recreated it and opened your project in S4L. This still didn't show your modeling objects but it did show your simulations and postpro.
I guess you could look further into the h5 file structure (comparing to a 'reference' one from another one of your simulations to check what else could be missing) or maybe you can mail the support team to ask for help recovering your data? Or hopefully you have some backup?
At the very least your results should still be safe and you can always drag and drop your results into sim4life to inspect them (they are the output.h5 files in the results folder ... not ideal I know).