Routinely I use the Disk Cleanup wizard and Disk Defragmenter for maintenance of my computer. When running the Disk Cleanup I have noticed there is a very large amount of compressed old files on the computer. I do not want these files, so how can I delete them from the computer?

Compress Old Files is an option available in the Disk Cleanup wizard. This instructs the Disk Cleanup wizard to compress files which have not been accessed in a particular period of time. The files are still available to be accessed, but are slower to access as they need to be decompressed. The rationale behind using this feature is that you can save on hard drive space by compressing these files, only decompressing the files on-demand when you do need to access the files. While this will be slower than accessing non-compressed files, since you don’t access these files regularly the performance hit when accessing these files is acceptable.

This feature was more useful when computer hard drives were relatively smaller in storage size and were expensive. In this day and age with 1 TB computer hard drives costing around $250 - $300, together with affordable external storage, conserving storage space on hard drives has become less of an issue and most people store anything and everything without much concern for occupying large amounts of hard drive space. In fact, if you have a hard drive with ample capacity I would recommend not using the “Compress Old Files” feature in the Disk Cleanup wizard as this may cause more problems than it solves, especially since you are compressing files and changing the way the files are stored on the computer.

Regarding deleting these compressed files, Disk Cleanup does not give you the option to delete these files purely because they are not designed to be deleted. The Disk Cleanup wizard is compressing live files on your computer which you may need in the future, but just have not used recently. Therefore, if you delete these compressed files you will be deleting real data from your computer, which you potentially may need to access again in the future.