After I installed sigma plot, when I create a new subfolder, I could not open excel under that folder. I have checked whether it has anything to do with read-only, but excel file in the other subfolders under the same folder can be opened. And then if I move the new subfolder which has the excel file up, parallel to the mother folder, the excel file can be then opened.
I then create a new folder parallel to the mother folder, put the excel file in, it opens fine. I move it into the mother folder, then it stopped opening again. What is the problem here?