There are three different types of ways to recover data with data recovery software:
1. Search for a missing Master File Table (MFT) - this search basically finds a missing partiton, are reads it.
It is a very fast search (i.e. usually less than 20 minutes).
2. Search for individual records within a missing MFT - If the entire MFT cannot be found and recovered, it is possible to search for individual records within the MFT to rebuild the old file and folder structure of the drive.
This search will take between 2-3 hours to complete.
3. A sequential search of the entire drive for indiviudal files - this search looks over the drive for individual file types recognized by their header, file structure, and footer.
This can be a long search. The time taken will depend on
- the size of the drive
- whether the search is done at a cluster or sector level
- how many different file types are selected to search for at a time (the more types, the slower it is)
- if there are any bad sectors on the drive (this will slow it down as extra time is needed to try and read bad sectors)
So it depends on how the data was lost, and running the rigth thype of search with Recover My Files.
Recover My Files v4, due out later in the year, will automate the process of selecting the right type of search, so it should make this process much faster and easier.
I hope this helps.