Part of Movebot's migration offering is the ability to run a pre-migration scan across your source environment to receive a comprehensive breakdown of your files, the distribution of those files and any file challenges that may be encountered when migrating data.
To run a scan, create a Movebot project and follow the wizard until you reach the Users/Drives stage. At this point click Add Full Org Scan and this will return you to the migration dashboard.
At this point select the organisational scan that was created and select Scan/Discovery. This will then kick off the scan and you will receive an email once it has completed.