Thanks a ton. I haven't played in three weeks due to moving, so I was wonder why the fuck neither of my RS cables suddenly weren't working. I was able to fix that problem by following these steps.
Go to the ToolKit, right click the icon, and select "Show Package Contents". Then select the folder "drive_c". I created a folder in here titled "CDLC", so I can drop PC customs and convert them to Mac. Once converted, make sure to copy/paste these new m.psarc files to the CDLC folder in Steam. Hope this helps.
Same situation here. Rocksmith Tool Kit works. I took the 6 GB-Version. Thank you very much for it!! BUT I can't select any DLC for platform conversion in the Converter! Any idea? Find the C-Drive in the file contents in the toolkit file. Make a CDLC file of what you want to convert then click and drag into the C-Drive. You'll be able to find everything in the file you made in the C-Drive. Now for me it was tough to figure out how to get everything back out. What I did was delete the converted files and then removed them from the trash bin back to my desk top and that worked for me. Ok but where is the C drive on a mac lol.
I'm still not able to use the toolkit on Catalina. Currently on 10.15.6. Whenever I try to open the toolkit dmg, it just says the file is damaged. I've attempted this on two different Macbooks. This sucks because not every creator provides Mac files for customs. I can't even get to the installation stage.