Symptoms
When a cube writeback commit transaction and a processing transaction are executed at the same time on an instance of SQL Server 2012 Analysis Services (SSAS 2012) or SQL Server 2014 Analysis Services (SSAS 2014), the instance crashes, and you receive a mini-dump file in the SSAS log folder.
Resolution
The issue was first fixed in the following cumulative updates for SQL Server:
Cumulative Update 2 for SQL Server 2014 SP1
Cumulative Update 6 for SQL Server 2014
Cumulative Update 4 for SQL Server 2012 SP2
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out 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.