I have run into a block where I am trying to resize an image for a show next month and both photoshop and lightroom will not allow me to export, save or even save as, an image. The error says I do not have permission to write that image, but in looking at the image info, I do have that. It is set for everyone to read and write. Super fri=ustrated and no clue where I need to go next.
You need the proper permissions on the folder where the exported file is going to be written. Go into your operating system and change the permission on that folder to WRITE permission.
Or change hte folder you are exporting to so that it is a folder you know you can write to, such as "My Pictures" or whatever it is called on your operating system.