What are these giant files in ~/Library/Autosave Information/? In my ~/Library/Autosave Information/ folder on 10.7, I have some fairly routine-looking files—a few unsaved scratch documents in applications that use Autosave, and accompanying plists for those apps. I also have 3 folders with names like 64FE2D0E-7447-4086-B7CA-8D59ED769875.genstore.noindex. They each contain a .genstore_lockfile file and a .genstore_staging/ directory, which contains another directory with a random name such as rneN5zs, which contains a single file, staged.

The problem is that the staged files are pretty big - 1.49 GB, 980 MB and 312 MB. According to the Finder's timestamps, they were created back in June, and haven't been modified or accessed since.

I'd like to free up that space on my drive if possible, but I don't want to go deleting these files without understanding what they are. The names and access times suggest they might be temporary storage for saved state data (although I'm not sure why it would be so big) that didn't get cleaned up. Running lsof doesn't list any process accessing those files.

Does anyone know what these files are? Do you have similar ones on your system? Can they safely be deleted?
Delete them, they are just caches for an app or an installer.

A lock file indicates that a process was using them while it was forcibly quit or crashed. Normally, when system processes modify files, they create a lock file for it so that no other process can access it. These files are deleted when the process exits or stops modifying the said file.

The presence of the lock files indicates that their process has not accessed them since they were created. That means you have probably not used the app involved. 

Source: https://superuser.com/questions/313878/what-is-a-lockfile