Latest Photoshop not functioning when opening CS3 files
I just recently subscribed to Photoshop 2021 when my CS3 license stopped working. I've had nothing but trouble when I try to open my CS3 files in the new version. Either Photoshop crashes, or the Efficiency drops below 20%, making it impossible to do the simplest tasks. Mind you, the files I'm currently working with are not that big. They range from 30MB to 120MB. My entire portfolio and in progress work is made up of CS3 files. Under crushing deadlines this is making my workflow impossible. Another thing to note. I tried to uninstall Photoshop CS3 yesterday which did not work. I kept getting a message that said it could not continue because Acrobat was open (it was not). My computer screen froze and would not shut down properly after that, so I had to crash it each time in order to restart. I managed to place the CS3 application in the trash and then I did a fix on the Creative Cloud app I downloaded a couple of days ago. Since then I haven't had any freezing of my computer, but I'm still having trouble with my files.
I'm running macOS Mojave. Processor: 3.1 GHz Intel Core i5 Memory: 16 GB 1867 MHz DDR3. Intel Pro Graphics 6200 1536MB.
I'm afraid to upgrade to the latest OS until I know I won't have issues opening my old CS3 files (they are my life's work).
Does anyone have any solutions? I'm pulling my hair out at this point.
Thank you!