To fix ms messing around so i can get some of my mapped drives back. Sadly my brain taking a ms day and for the life of me i can't remember how. MS16-072 changes the security context with which user group policies are retrieved. This by-design behavior change protects customers’ computers from a security vulnerability. Before MS16-072 is installed, user group policies were retrieved by using the user’s security context. After MS16-072 is installed, user group policies are retrieved by using the machines security context. Why it happened: This issue may occur if the Group Policy Object is missing the Read permissions for the Authenticated Users group or if you are using security filtering and are missing Read permissions for the domain computers group. How to fix it: To resolve this issue, use the Group Policy Management Console (GPMC.MSC) and follow one of the following steps: Add the Authenticated Users group with Read Permissions on the Group Policy Object (GPO). If you are using security filtering, add the Domain Computers group with read permission.