I have updated from 5.62 to 6.01 and I have a big problem. When a user (anyone) tries to upload an image, the fields of categories that not apears, and the image can not be uploaded.
Please make sure you have uploaded all the 6.01 files and recheck upload permissions in admin edit categories in admin and make sure the proper usergroups have upload permissions. Let me know if this solves your issue.