Autosave is a feature which automatically saves a dirty file (any file with unsaved changes) in the background when you are not working on it. Therefore, if you simply open a file and look at it, no autosave occurs. Similarly, as you are working on the file, no autosave occurs, but as soon as you stop working, the file is autosaved. 

This means that in the unfortunate event that your computer crashes or you suffer a power failure, you will not lose any work. When you re-launch AVA the file will re-open and will contain all the changes you had made to it.

You can choose to turn this feature on or off per document, and the state of the function (on or off) is saved with the document. This means if you save a document with autosave off, the next time you open the document autosave will still be disabled. By default this is always switched on.

One reason you may choose to turn this off would be if you are working on an extremely large file where the autosave function may impact on your productivity. In cases like this, you may turn the feature off for a short period of time, then switch it back on later.

When you turn this off, any autosaves which are currently in progress are immediately cancelled. If you choose to switch this back on, AVA will schedule an autosave immediately for any unsaved changes.