Transform error in Power Query 'The key didn't match any rows in the table.'

[reporting_95]

Hello everyone,
I'm trying to merge multiple excel files into one spreadsheet using Power Query, but I receive the following error when doing so:

An error occurred in the ‘Transform File’ query. Expression.Error: The key didn't match any rows in the table.
Details:
Key=
Item=Client Lists
Kind=Sheet
Table=

Now a bit of information on my data sheets. The workbooks I'm trying to combine are tabled and also contain 2 tabs each. I'm trying to specifically combine 1 of the tabs from each sheet. In the Power Query navigator, it shows the options of 'Table' and the named tab I want to focus on.

I tried to separate the 1 specific tab into one book and ensured all of my books have the exact same headers. When I try to combine I still receive the same error.

Do I have to un-table my sheets? Or do I have to create a new book for the specific sheet I'm looking to combine? Please help!
Thanks

 

[Alex Blakenburg]

The most likely is that one of you path\filename\sheet_tab names is no longer valid.
If you have pulled each file in as a separate connection check each query to see if one of them has failed.
I assume you are doing a Merge.