A question about butterfly

it always displays WindowsError when I’m done installing.

Can you post the full error report from report output? In which line it happens. This error means that Butterfly cannot remove an existing file. Any chance that you have the file open in another application?

After butterfly has been installed, I have tried to open several files, everytime it had the same error. I didn’t open the same file in another APP at the same time.

According to your post, I can not help you debug you model. PLease upload your grasshooper definition. If you have no right to upload file,please share some link such as Google Drive\Dropbox.

The picture is example files for butterfly which i upload. It can be found in the installation file.