I have the following issue:
I am reading multiple Excel Files from one Folder. One column is present in every file, but not filled in every file. Therefore, during the read-in loops, different column types are being detected and the loop / read-in fails.
Are you using loops or built-in option Excel Reader has to read multiple files? If first then in Loop End node check option to Allow changing table specifications.
Also there is option in Excel Reader to Skip empty columns. Uncheck that option and you should then have same structure for each file each time and above setting might not be necessary.