Now, I could manually run a search in Windows Explorer for all *.pst then copy them elsewhere. Problem with that is most of our users PST's are going be saved as the default 'Personal Folders(1).pst' meaning Windows would constantly prompt me to overwrite or save both. Also, with this naming convention, once all PST's are in one big storage area, I would have no idea whose PST is who.
The only way I can think of getting round this is to use Robocopy.exe to replicate the Home directories folder structure onto the storage disk and only copy PST files, ignoring all other file types. This way, there would be no conflicts and prompts to overwrite and I would also know who's PST is who from the folder path.
On the server which contains the Home directories, run the following from command prompt:
ROBOCOPY d:\home \\storage\restores\temp *.pst /S
d:\home is the drive and folder which contains the home directories for each user
\\storage\restores\temp is the server, share and folder where I want the folder structre and PST's to be copied
*.pst means that only .PST files will be copied
/S means the folder structure and any subfolders will be copied, only if they contain .PST files
Unfortunatley in my scenario there is still a bit of manual work required. I would need to go into each users home directory (on the copy on the storage disk), and rename each PST to Mimecasts required naming convention. To assist, you could create a script. The the easist way (that I know of) is to output the directory structure (dir /b /s *.pst >c:/pstdir.txt), open as an Excel file and use the concatenate function to firstly build the new filename, then a 'ren' (rename) command.
You should end up with something similar to below for each row which can be copied into a bat file or directly into command prompt.:
ren "\\storage\restores\temp\joe.bloggs\My Documents\Outlook Files\Personal Folders (1).pst" "email@example.com"
A list of Robocopy commands can be found here