On 9/14 , we downloaded and installed:
Microsoft Dynamics CRM Server Update 1.0 (KB3154952) Version 8.1.0000.0359. Since the install there have been the following problem:
When clicking on Administrator > System Settings the following pop-up box appears which says:
Query Builder Error The specified field does not exist in Microsoft Dynamics CRM
pop-up box 
Whether the Upgrade has cause this issue, I do not know; its been several weeks since I had last gone to System Settings. but before 9/14 System Settings was accessible. Please help. Obviously need to get into System Settings !