Peter (RL) (7/20/2020)
Hi Dorothy
I've tried both processes and they work fine for me so it isn't a general CC3 issue. It sounds as though CC3 is not able to write to the drive correctly to replace the content or change the thumbnail.
Have you changed the permissions settings on your computer recently or installed any new security software that may have made changes?
Also, are you able to save new content instead of using replace? If so it may be that your existing content files permissions have been changed to read only which will prevent them from being written over.
so, its very strange. It sometimes works but sometimes doesn't. I haven't made any changes to my computer. I might do a fresh install to see if that helps.