Cannot overwrite old files

I installed a new DAW and connected all data drives as usual. I have built my DAW many times and had no problem until this time, strangely, all old Nuendo projects ( and Cubase projects, I also run Cubase 8.5 ) cannot be saved over. I have Auto-save on and every time Nuendo auto-save it will alert me that the npr projects cannot be written over and it will save in whatever name-01.npr then the next auto saving time, whatever name-02.npr etc… The strange thing is that besides not being able to overwrite the old file, it cannot auto save in BAK file which is the default for auto save. I have checked the drive is not write protect.

Then I deleted the old npr file ( backup first of course ) and saved it using the original name, then everything is back to normal, it will save in BAK again. Anyone can explain this behaviour?

Maybe your old backup files are read-only!?
Or you don’t have the proper permissions to overwrite the file.

Fredo

No, it is not that. They are not read-only.