Symptoms
Assume that you are using Microsoft SQL Server 2012 Analysis Service (SSAS 2012) or SQL Server 2014 Analysis Service (SSAS 2014) with roles that use cell security expressions. When a cube writeback commit transaction and a processing batch are executed at the same time, the SSAS instance may crash.
Resolution
The issue was first fixed in the following cumulative update of SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. We recommend that you download and install the latest cumulative updates for SQL Server:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.