4,8Gb : Yes isn't enough.
If launcher consider install as failed, install need more space (and then need more space than needed by patch).
Consider this : You need space for download, space for temp, space for extract file and space for patching.
As above : clean trash files, reduce Window's temp file size, delete DiskCacheArena (space = 1Gb), for help install.
Warning when you clean files / reduce file's size : maybe system needed create again this file, and you may not enough space for launch games after. If you have less 1gb free you can't launch game!. Then if case, consider buy more space.
