Windows 10 Anniversary Update does like all its predecessor updates and retains old Windows files so that users can roll back to a previous version. In doing so, many hard drives are left with the skeletal remains of obsolete features and mounds and mounds of files taking up unnecessary space. And, in most cases, this stolen space can amount to GB’s of storage.
And, yes...those pictures below are correct. I, personally, had over 17GB of old OS files to remove. Your mileage may vary, but I suspect a lot of you will find that Windows 10 Anniversary Update stole quite a bit of your precious hard disk space.
When you’re positive that you no longer want to rollback to an earlier version of Windows and you can to reclaim the space for other things, do this…
Go to Settings > System > Storage and then tap or click This PC (C:)
Next, scroll down to Temporary files and tap or click on it.
Check the Previous version of Windows option and then tap or click Remove Files.