USMT.TMP hidden folder on drive C: – whats that about ?

A client who inherited an old machine from another user was asking about space on drive C as their applications were complaining bitterly about a lack of space. Given that the main use of drive C for this user was temporary files and the apps they use which hadn’t changed – the question was – whats using up the space. Usually the first thing I do is install Treesize Free to get a handle but straight away my eye was drawn to a folder called USMT.TMP which was using 12GB of the users very small 70GB disk.


So what is this folder and why has it got files that are many years old in it. Put simply these files were created when the machine was commissioned. User State Migration Tool (USMT) is a tool that Microsoft provided to allow files and settings from one machine to be transferred to another. Looking at the dates on the files and folders in the directory confirmed this. The redundant files were duly dispatched by deleting them – not placing them in the recycle bin. The user was then advised to run a disk defragmentation as the previous low space condition can tend to cause fragmentation of files if allowed to persist for a period of time.