A. When a machine is in a domain the domains EFS recovery agents is used to decrypt files for which the user has lost their private key.

In a workgroup or in a 4.0 based domain the recovery agent is the local Administrator so its vital to backup the Administrators private key. To do this perform the following:

  1. Logon to the computer as the local Administrator account
  2. From the Start menu select Run
  3. Enter the name 'secpol.msc'
  4. Expand the 'Public Key Policies' branch and select 'Encrypted Data Recovery Agents' leaf
  5. A certificate for Administrator with the role of 'File Recovery' will be displayed
  6. Right click on the certificate and select 'Export' from the 'All Tasks' context menu
  7. The certificate export wizard will start. Click Next
  8. You have the option to also export the private key, select Yes. Click Next
  9. Make sure 'Enable strong protection' is selected and click Next (you also have the option of removing the private key after it is backed up)
  10. Enter a password for the exported key. Click Next
  11. Enter the name for the exported file. Click Next
  12. Click Finish
  13. Click OK when the export is complete
  14. If you choose to remove the private key after export you should now restore the computer

A file will now have been created in the target location containing the certificate. Make sure you keep it safe. Its only about 2KB.