Writing to Excel problem - TTtoolbox Plug-in

I'm using the write to Excel Component from TTtoolbox with no problems at all, until yesterday I tried it on a new computer, and it kept opening a new Excel file every time Galapagos runs a new iteration, any idea how can I fix that. I used to have all iterations written to one Excel file. now I have to deal with as many as 1200 Excel files!