In Origin earlier versions, the autosaved opju was deleted in the following two cases:

1. after successful save.

2. after project is closed.

Origin 2021b changed to make a copy of the autosaved opju before it is deleted on case 2(closing project). The file has a fixed name "Last-AutoSave.opju". 

For any project in the AutoSave, Backup, Unsaved folders, Origin 2021b will

1. Skip Autosave,

2. Skip saving Unsaved

3. No adding to Most Recent File List