Here are my steps:
- Get Data \ Folder \ Connect
- specify the Folder path
- Combine & Load
- select one of the files as my sample file; click on the file name as my Parameter1; click OK
After I click OK, the cursor spins for a bit, and then it stops. Nothing happens. So, I go to Edit Queries \ Edit Queries. There is a warning symbol on my data query that reads:
An error occurred in the 'Transform File' query. Expression.Error: The key didn't match any rows in the table.
Details: Key = Item=200704 Kind=Sheet Table=[Table]
How do I resolve this error?
If it helps, Power BI generate 5 queries for me, and the structure is:
- Transform File from data 
- Helper Queries 
- Parameter1 (Sample File)
- Sample File
- Transform File
- Transform Sample File
- Other Queries 
Interestingly, if it helps to diagnose the issue, if I set sample file = First file or if I set sample file to my first file manually, the following error is thrown in the dialog, but it doesn't show what query is in error when I try to view / edit the query.
Failed to save modifications to the server. Error returned: 'OLE DB or ODBC error: [Expression.Error] The key didn't match any rows in the table..'.
And, to be sure, when I attempt to load this file (or any file in the folder, for that matter) individually (via Excel connection), it loads successfully. So, something must be wrong with the M code in my Folder connection.