We're sorry about the trouble with Photoshop Elements 2020. Are you getting an error saying that the Scratch disk is Full? If yes, please check the amount of storage available on your computers drive. The scratch disk is basically the amount of free space on the computers storage that Photoshop requires to create the necessary temporary files while launching and working on project files.
Please try creating more space on the drive or you can add another drive as an alternate scratch disk in Photoshop Elements by going to the Preferences, then Scratch Disk.