Symptoms
Assume that you install Microsoft SQL Server 2016 Analysis Services (SSAS 2016) or SSAS 2017 in multidimensional mode. When you process the dimensions by using the Process Update option, you may receive an error message that resembles the following:
Internal error: An unexpected exception occurred.
Resolution
This issue is fixed in the following cumulative updates for 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. Check out the latest cumulative updates for SQL Server:
Workaround
You may work around this issue by performing a Process Full operation before the Process Update operation. Because this issue only occurs when you perform the Process Update operation after the SSAS service is restarted.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminologythat Microsoft uses to describe software updates.