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ScottBeal Frequent Visitor
Frequent Visitor

Preview Error

We are receiving the error "Preview.Error: The type of the current preview value is too complex to display." in Power Query Editor.

The table that is giving the error has worked up until sometime over the last few days.  The table is just one table of our larger datawarehouse in Amazon Redshift.  The table in question only has 28 columns and 238 rows.  The column datatypes are bigint, varchar, and timestamps.


We tried with the existing dataset to refresh, replace, clear cache with no success.


We also created a new dataset and chose only that table but received the same error.  If we cancel the refresh and then drag the columns onto a report grid the data looks correct.  The issue is that this table needs to be used in conjunction with other tables in the Query Editor and the Preview Error prevents that.


We do not see anything abnormal when selecting records through any SQL client.


Thanks in advance for any ideas/advice/answers.



Microsoft v-cherch-msft

Re: Preview Error

Hi @ScottBeal 

I would suggest you update to the latest version of Power BI Desktop to test again and check if this post could help you.



Community Support Team _ Cherie Chen
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
ScottBeal Frequent Visitor
Frequent Visitor

Re: Preview Error

@v-cherch-msft  Thank you for the reply.

We are using the latest version of Power BI desktop (Version: 2.67.5404.981 64-bit (March 2019)).

The post that you refer to was solved by reverting to a previous version of the "file".  At which point the user says only a few steps were missing (not added yet) and it worked.


We have no file to revert back to.  However we can create a new .pbix, add just that simple table, and encounter the same error.


Below are images of the PBI Editor and the table schema, for context.  Both are very simplistic.

I can only guess that the error is due to some data in the table causing PBI to error out.


Person Preview Error #1.pngPerson Preview Error #2.png


Person Table Schema.png

ScottBeal Frequent Visitor
Frequent Visitor

Re: Preview Error

With further investigation, the error seems to be related to foreign keys.


Here is one scenario that causes the error:


The table in question is a "Person" table.

We have a phone call table, with fk references to person, for the caller and recipient.

We also have a sales lead table, with fk references to person, for acct manager and sales rep.

With 2 references from each table we receive the "Too Complex Error".

If we remove any one of the 4 fk references (so that there are 2 from one table and 1 from the other) the "to complex" error goes away.

We also added a third fk reference to one of the tables, so that there is 3 from one table and 1 from the other.  This also caused the error.





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