can you please have a look at the end of the KNIME log file right after the error occurred and post the detailed problem here. To view the log file go to View → Open KNIME log.
Also you might be consider to update to the latest version which contains a complete rewrite of the Excel Writer which now also allows you to append to an existing file. For more information about the new Excel Writer and the new file handling framework in general have a look at this blog post or the file handling guide.
Yeah I did that and the log showed that the problem was due the size of the excel file (80MB) , I then tried it with a sample and it worked. Regarding the new version as I’m using the company’s Knime I have to wait for them to update it, but I’ll definitely talk with IT.
Thanks for the suggestions.