question

Sounds like there are some calculated measures in the cube which need the data from the measure group which did not get processed but should have been processed based on the actual dimensions' changes. For example, there might be some hybrid calculations, such as give me the actual sales for the periods which already have history (in the past) and fill in the forecasts for all future periods which don't have the actual sales yet. This might explain why the problem is occasional, it depends on the dimension changes so it might be irrelevant to some reports/slicers combinations. If the report can afford filters without multiple selected values so that double-clicking one of the values' cells in Excel opens up a new sheet showing the underlying factual data, then the data in that sheet may be examined versus the T-SQL script against the same fact table in the relational database, just to see whether results are the same or not and why.

Thanks Oleg, But I am confused as if it related to the dimensional change then is it possible that it will fail all the reports at the same time with same error. As I am unable to execute any of my reports at that time. Anushka.

@Anushka92 When this happens, do you see that there are empty cells in the values area where you expect some values to appear? If so then you can try to write the equivalent T-SQL query against the underlying database and compare it with the results of the MDX. In case if you don't have the [OLAP PivotTable Extensions][1], consider installing it. This add-on to Excel is very useful because it lets you see the MDX generated by Excel (among many other useful features it has). Taking the generated by Excel MDX to SSMS and examining it there can help to identify the problems with reports. What can really help with identifying the root cause of this problem is trying to ping @Pavel Pawlowski and @Scot Hauder to this thread. [1]: https://olappivottableextend.codeplex.com/wikipage?title=Excel%202013

Hi this time when I faced this problem, I have taken the backup of cube and the restarted the SSAS service. after restarting service the error disappear. then I tried to restore the backup on Dev server and tried running the reports against it and the reports are working fine this time without any mdx error. This means there is no problem with Cube structure rather it is a bug in SSAS. can you please confirm this and also what to do when faced next time. Anushka

@Pavel Pawlowski, @Scot Hauder please could you guys have a look at the thread conversation and help me in determining the root cause for this. Anushka