Hi @kevthekelt, We did some testing here. I think I understand what's happening:

When you change the source data, the reader doesn't know if the new file has the same schema (data structure) as the previous source file. So it doesn't want to assume the previous setting still works for the new file, and revert to the default settings instead.

There is a way around this:

Please add the Excel reader again, so you can set the reader parameters again. Near the bottom of the parameter dialog, there is a parameter called "Additional File Settings" Change this to "Use Current Settings"

This let the reader know that any additional file you read with this reader should be considered to have the same schema as the original and all settings should still apply.

Please give this idea a try and see if it works any better. Thanks!

Sorry for the late reply, but that suggestion didn't work. I've logged this as a critical bug as I feel it's a bit of a show stopper!!

unfortunately that didn't work. I've logged this as a critical bug as it's a real show stopper and some of my projects are on hold.