Skip to main content
cancel
Showing results for 
Search instead for 
Did you mean: 

Be one of the first to start using Fabric Databases. View on-demand sessions with database experts and the Microsoft product team to learn just how easy it is to get started. Watch now

Reply
BryanCarmichael
Advocate I
Advocate I

Gen2 Dataflow load to Lakehouse error - We cannot convert the value null to type Table

I am inconsistently getting this error across refreshes when loading to a lakehouse from a Gen2 Data flow (this is loading from an original dataflow)

Sometimes the refresh completes - sometimes it does not - when it fails on seemingly different entities within the Gen 2 dataflow I receive the following error.

'null Error: Couldn't refresh the entity because of an issue with the mashup document MashupException.Error: Expression.Error: We cannot convert the value null to type Table.'

Any help greatly appreciated

1 ACCEPTED SOLUTION
BryanCarmichael
Advocate I
Advocate I

This should now be fixed - we worked with the product team and it was addressed in a release last week

View solution in original post

16 REPLIES 16
mkruk
Frequent Visitor

Is there any movement on this subject as I am getting the same error loading from Synapse to DF Gen 2.

The issue from this topic was previously addressed. If you're encountering this error message, the root cause might be a new one. Could you please create a new topic / thread and add as many details as possible as to how to replicate the issue?

BryanCarmichael
Advocate I
Advocate I

This should now be fixed - we worked with the product team and it was addressed in a release last week

Hi there, I upgraded the gateway as suggested.

Still getting the same error!?:

Mashup Exception Error Couldn't refresh the entity because of an issue with the mashup document MashupException.Error: We cannot convert the value null to type Table. Details: GatewayObjectId: 6dbdaa7f-85eb-44e3-93b9-627e525dca7f

Any help would be appreciated.

Many thanks

Please reach out to our support team so they can take a closer look with the engineering team. You can use the link below to raise the support ticket:

https://support.fabric.microsoft.com/support

SidJay
Microsoft Employee
Microsoft Employee

Hi Bryan,

 

If you're able to share a few Request IDs and Session IDs for recent failures with this issue, we can start to look into the issue in parallel (while a support ticket is filed).

 

Thanks

Hi Bryan,

 

Thanks for confirming that this is now fixed. The fix requires updating to the latest Gateway (3000.182.5) released on August 2nd.

 

Thanks

Anonymous
Not applicable

Hi,

 

Exactly same error message. Did you get any solution? Thanks

I have a call with a Microsoft Engineer tomorrow morning - will update after that.

 

Just out of curiousity how are you trying to load data ? we see this issue with dataflows, sql server, oracle databases and sharepoint as sources.

We have a cluster of gateways and our capacity is hosted in EMEA 

Anonymous
Not applicable

I am using a SQL Server on-prem as source with latesest version of the gateway. 

From source to dataflow, all tables work but from DF to lakehouse, random tables are failing.

This is one of the error messages I can have

Sounds like exactly the same situation - once i have met with the Microsoft aupport engineer I will update this post

Could you please try upgrading to the latest Gateway (version 3000.178.9 released on June 15th). That should help address at least one class of errors involving output destinations and/or queries that depend on other staged queries.

 

Please let us know if the issues persist after that. Thanks.

Hello SidJay,
I have updated the gateway and manually restarted the loading. No more errors!
I'll wait for the scheduled executions and update my post.

thanks

miguel
Community Admin
Community Admin

Hey!

Are you using a gateway by any chance? I'd recommend upgrading to the latest version of the Gateway. If that is still giving you issues, please reach out to our support team so they can do a more thorough investigation.

I am using a cluster of gateways both with the latest release  - whats the best way to contact the support team ?

 

You can create a support request through Microsoft Fabric Support and Status | Microsoft Fabric

Helpful resources

Announcements
Las Vegas 2025

Join us at the Microsoft Fabric Community Conference

March 31 - April 2, 2025, in Las Vegas, Nevada. Use code MSCUST for a $150 discount!

Dec Fabric Community Survey

We want your feedback!

Your insights matter. That’s why we created a quick survey to learn about your experience finding answers to technical questions.

ArunFabCon

Microsoft Fabric Community Conference 2025

Arun Ulag shares exciting details about the Microsoft Fabric Conference 2025, which will be held in Las Vegas, NV.

December 2024

A Year in Review - December 2024

Find out what content was popular in the Fabric community during 2024.

Top Solution Authors