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tomerbi
Helper I
Helper I

Collection was modified; enumeration operation may not execute.

Hello, 

 

I'm having a problem since already for a few days trying to refresh the data on my Power Bi desktop. The power query editor refresh is successful with no problem and the processing time isn't long but when I try to refresh this on my PBI, the loading time is quite significant while showing "waiting for other queries" and then ends up with "Collection was modified; enumeration operation may not execute" 

 

In this case, my data sources and credentials are valid and possible to fetch since there's no problem refreshing on the Power Query Editor side. (Sources: web API and web excel from OneDrive)

 

I'm using the latest version of PBI and have tried looking around from clearing caches etc. with no help. I'm not sure what's wrong with this, it never happened to me before. I would appreciate any suggestion very much. 

3 REPLIES 3
Anonymous
Not applicable

Hi,@tomerbi I am glad to help you.
Hello,@mh2587 thanks for your concern about this issue.

Your answer is excellent!
And I would like to share some additional solutions below.

 

You can try to use dataflow as data source for data joining to create a report
Since you mentioned that your data is executing fine in Power query and it takes less time. So you can consider to create a dataflow with the same function as the original data source, and use the dataflow as the new data source for data fetching. At the same time, the report using the dataflow as a data source does not need to create a gateway connection to its semantic model on the services. You just need to create a schedule refresh for the dataflow separately. This bypasses the usual gateway connection configuration.
Dataflow can be thought of as a power query on the cloud service. If your report data is processed correctly in the power query, it should be processed correctly in the data stream.

On this basis, you can try to optimize your data structure, avoid too complex relationship structure, if possible, please reduce some unnecessary data, so as to reduce the burden.
I hope you find the following documentation helpful:
URL:Creating a dataflow - Power BI | Microsoft Learn

I hope my suggestions give you good ideas, if you have any more questions, please clarify in a follow-up reply.

Best Regards,

Carson Jian,

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.



mh2587
Super User
Super User

See the following thread
https://community.fabric.microsoft.com/t5/Service/Power-BI-Scheduler-Refresh-Fail-Collection-was-mod...


Did I answer your question? If so, please mark my post as a solution!


Proud to be a Super User!




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Muhammad Hasnain



Hi @mh2587  

Many thanks for your help. 

All of my credentials setting is set to organizational level but it still doesn't solve the issue. 

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