Forum Discussion
Formula.Firewall: Query references other queries, so it may not directly access a data source.
Ken Puls blogged about this here
http://www.excelguru.ca/blog/2015/03/11/power-query-errors-please-rebuild-this-data-combination/
All of my data retrievals are now done in external functions
- edicated functions which also do some manipulation of the data before returning it
- a standard fLoadSheet function which is simply passed the name of a sheet in the spreadsheet and loads and returns it
However, yet again, I had a problem with this frustrating error. I called a standard function to return some parameters from a parameters sheet. Suddenly I got the Firewall error.
Given that I have written some VERY complicated scripts which retrieved data from various sources and worked no problem but written other scripts which are not (seemingly) as complicated but have failed with this error, I am still of the opinion that this is Microsoft's catch-all, can't cope error message!
Also, I sometimes get this error when stepping through the code (in the "advanced editor") but not when running the script, explain that!
This is madness.
I have tried using staging queries, and also making data retrieval in custom functions. None worked.
I'll probably have to start using a data lake to make simple merges between data sources, only because of this issue.