Showing results for 
Search instead for 
Did you mean: 
New Member

Optimize consolidation (append) of tables

Hello all,


Will much appreciate help with the (apparently) simple issue I'm having:


I have a Power BI file that loads information via Power Query of all the Excel files in a folder. I need to calculate the incrementals of figures between some of the atributes (tabs of the Excel files), for example, "optimized scenario" minus "base scenario", to achieve this, I make additional tables to calculate this difference.


All good up to here, runs fairly quickly. the problem is when I want to consolidate all the created tables (always around 12 tables) using the append function, it takes way more time to process than all I have described before. The screen that shows the progress of the load process finishes quickly with all the tables until it reaches the appending part. I made sure that the only thing the final table (the one I append everthing to) does is append, but it always gets stuck there, cycling through each Excel file in the source folder multiple times.


Any idea on how to optimize this would be greatly appreciated, I believe it is a small thing I'm missing that's causing this.


Thanks in advance.



Super User IV
Super User IV

@ImkeF , have any thoughts?


@ me in replies or I'll lose your thread!!!

I have a NEW book! 
DAX Cookbook from Packt
Over 120 DAX Recipes!

Did I answer your question? Mark my post as a solution!

Proud to be a Super User!

Hi @Wolfgang7 ,

there could be many reasons. Please check my list here: 


Imke Feldmann (The BIccountant)

If you liked my solution, please give it a thumbs up. And if I did answer your question, please mark this post as a solution. Thanks!

How to integrate M-code into your solution -- How to get your questions answered quickly -- How to provide sample data -- Check out more PBI- learning resources here -- Performance Tipps for M-queries

Helpful resources

PBI User Groups

Welcome to the User Group Public Preview

Check out new user group experience and if you are a leader please create your group

April Update

Check it Out!

Click here to read more about the April 2021 Updates!


The largest Power BI virtual conference

100+ sessions, 100+ speakers, Product managers, MVPs, and experts. All about Power BI. Attend online or watch the recordings.


Experience what’s next for Power BI

See the latest Power BI innovations, updates, and demos from the Microsoft Business Applications Launch Event.

Top Solution Authors