Methods used in the preservation of documents or e-mail will depend on what is required for the litigation and the media that is being preserved.   Before getting into any detail, however, engaging a professional forensic technician with the right tools is always the safest way to preserve data.  The professional forensic technician will always preserve data so that files and the metadata are maintained in their original form.  Finally, if there is any possibility that the person executing the preservation will be called into court, you will want to use a professional forensics examiner.

There are times in document production when metadata is not important and the origin of the ESI is not in question.  Under these conditions any IT person can copy and supply the data for production and review.

In addition, extracting e-mail files from servers can also be done without compromising the metadata of the individual e-mails.  For example, the most common e-mail platform on the market today is Outlook and most companies use Outlook Exchange.  When the Outlook PST file is preserved the metadata of the individual e-mail is maintained.  Be careful, if individual e-mails or MSG files are preserved, the metadata will change. 

Other e-mail platforms work similarly to Outlook but always contact a forensics examiner to ensure you are protecting the data.