Forum Discussion
Memory allocation error on DAX table UNION 50M+ rows
Trying a quarterly csv file based data refresh and then doing a DAX table union join of old quarters and new quarters - I now get a memory allocation error. Queries to the csv files load correctly. ...
It might be a better choice to do your joins/appends within the query editor and not via DAX. The memory usage and compression will be more performant that way.
As for the firewall error, this is a well documented issue.
https://www.excelguru.ca/blog/2015/03/11/power-query-errors-please-rebuild-this-data-combination/