This happened to me - I just removed the Network Access account from the SCCM console and re-added it. I didn't have to touch my PE boot files.
From: [email protected] [mailto:[email protected]] On Behalf Of Christopher Duszynski Sent: Wednesday, 6 November 2013 12:55 PM To: [email protected] Subject: [mssms] ConfigMgr 2012 R2 Upgrade After upgrading to SCCM 2012 R2 when I update my PE Boot files it does not add in the Network Access accounts. I have removed them and re-added them with no luck. Any Idea? ________________________________ CONFIDENTIALITY NOTICE AND DISCLAIMER The information in this transmission may be confidential and/or protected by legal professional privilege, and is intended only for the person or persons to whom it is addressed. If you are not such a person, you are warned that any disclosure, copying or dissemination of the information is unauthorised. If you have received the transmission in error, please immediately contact this office by telephone, fax or email, to inform us of the error and to enable arrangements to be made for the destruction of the transmission, or its return at our cost. No liability is accepted for any unauthorised use of the information contained in this transmission.

