When you are a damaged PST or OST you get this.
Please give me a % complete (and any other info, like the part it is up to)
It should also alert users that this is not fixing corrupt data.
Eg. This is a consistency check only checking the free space – the non-data regions of the file (the free space that needs to be used). Therefore, this check progresses has nothing to do with the data itself (i.e. it is not folder-by-folder, it is region-by-region in the file).