What printer and what operating system? Many messages under this topic had to do with Windows 8 and a specific Canon printer. A variety of solutions have been offered, some more time consuming than others. My own problem was with Photoshop Elements 14, a Pro-100 printer, operating under Windows 7 Professional 64 bit. I received that same error message about the print being prepared but another computer was using the printer. When I checked the status of the print, it showed that the print was 51.6 MB, when I was in fact trying to print just a 6 MB image. I believe my problem started when I tried to print a photo package of 4 images on one 8.5 x 11 inch paper. The accumulated size of that print job may have been 51 MB. I received that error message, cancelled that print package, and could never get beyond the error. I cancelled the small image job, unplugged the printer, rebooted the computer, rubbed my stomach and patted my head. I finally deleted the printer definition and reinstalled it. This time I selected "do not share" on the network. The sharing may not have had anything to do with this problem, but I do not need to print off any other computer. My print at last started to process, but it was still showing as 51.6 MB. It went through, verrry slowwwly, and when finished the job cleared and the next print went through at the actual size in normal time. My problem was potentially solved by 2 things I did, not a good experimental approach, but there you have it. Good luck.
