If when you launch content you see the fade and then get immediately kicked back to the menu this thread is for you.
This is often from the core assignment not being properly set or having old assign files from a previous version of muOS.
First go to Applications → Task Toolkit → Clear Core Assignments ( May be under the Clear Tasks folder depending which version of muOS you are on )
Then go to Explore Content and open the content folder you want to assign so that you can see the roms/files i…
This should fix your issue. It’s almost certainly from old files. Same with Collections and History if you have those from previous versions, they will not work.