KB: No IUSR account access after you install the ConfigMgr client on a server running a multicast DP

When the Configuration Manager client is installed on, or uninstalled from, a server that’s running a multicast distribution point (DP), the IUSR account permission is removed from CCM/SMS_CCM folder. This causes multicast to stop working. Additionally, you may receive the following error message:

Call to HttpSendRequestSync failed for port 80 with status code 401, text: Unauthorized” in mcsmgr.log

Note that this issue affects Configuration Manager 2012, Configuration Manager 2012 R2 and Configuration Manager Current Branch. For complete details please see the following:

3205795No IUSR account access after you install the Configuration Manager client on a server that’s running a multicast DP (https://support.microsoft.com/en-us/kb/3205795)

J.C. Hornbeck, Solution Asset PM
Microsoft Enterprise Cloud Group

ConfigMgr 2012 R2