What specifically was wrong with your autosave file and can you share it? The autosaves should (of course) never be broken but without specific information there is almost no hope of being able to fix any problems there may be. AFAIK for the vast majority of users it's working fine.
More backups are better so if possible also set up alternate backup folders. There should also be auto-backups in addition to auto-saves, so with the right settings you can have six backup levels of your project (the main file, the autosave, the autobackups, and three additional backup folders). With all of that you should never lose work even in a worst-case scenario.
There are lots of reasons files can become corrupt and they're not always Construct 2's fault - for example some "helpful" system tools "clean" your temporary files for you, and promptly nuke all the unsaved project data Construct 2 is holding in temporary files, which can corrupt your project. Failing storage media or buggy storage caches and drivers can also cause problems.