can not open excel files

​@TKD-M The error says that it was an “unknown error”. A couple possible solutions:

1. Check the file itself for corruption. Make sure it opens correctly in Excel.
2. Make sure you don’t have the file open in Excel when running the automation.
3. In a worse-case scenario, you may have to perform a refresh of your installation of Microsoft Office. You do not need to remove it, just perform a refresh, kind of like installing on top of itself to fix any missing/corrupted/unregistered files.

Check those things first, then we can move onto other ideas if necessary.