Are these packages running in series or parallel? Are they all hitting the same DB?

The error message you posted is not overly helpful.

Usually (as the message itself suggests), a more specific and helpful error can be found before that one. Please take a look...

In the Flat File Destination Editor, is the 'Overwrite data in the file' option checked?

Well done!

Not a lot of upvotes against that post!

Please post back with any findings.

Presumably you want to do this in a SQL query? Or is this an Excel question?

Can you add a sheet to the spreadsheet showing how you would like the results...

Thank you Phil, I think that will work when I do deploy to the SSISDB.

At the moment, dataverse is constantly being update with a new/deleted/updated columns which is why...

You are correct, my apologies!

You can avoid all parallelism by using the Sequence command in your JSON and setting maxParallelism to 1.

https://learn.microsoft.com/en-us/analysis-services/tmsl/sequence-command-tmsl?view=asallproducts-allversions

Default, Full, Clear and Recalc are the options I'm seeing on the 2017 Standard Edition I have immediate access to.

Assuming you have deployed to SSISDB ...

Use an environment in SSISDB and create a sensitive parameter to contain the secret value.

Configure your SSISDB project to reference the environment and then...

You may find this article an interesting read … it is relevant to your question. Not that it solves anything!

https://www.sqlservercentral.com/articles/antipathy-for-entity-attribute-value-data-models

Based on your description, it sounds like you may already...

Are you able to provide more details about this issue? I know...

DROP TABLE IF EXISTS #SomeData;

CREATE TABLE #SomeData
(
    SomeId INT IDENTITY(1, 1)
   ,SomeText VARCHAR(10)
   ,CONSTRAINT PK_Nonsense
     ...

Is it so difficult for you to ask a question?

Can anyone provide the T-SQL code I need to amend an identity column from INT to BIGINT, please?

I am guessing that...