/storage/emulated/0 is missing. Apps can't find the directory
It may be that it is now located at /storage/sdcard0  since you flashed different ROMs with different configurations as you suggested,

alternately to run the following in emulator ;

mount -w -o remount rootfs /


then ;

ln -s /data/media/0 /sdcard


You can check with ;

ls -l -a /sdcard


Credits:


/storage/emulated/0 missing
Android 4.3 breaks Lil Debi. sdcard: '/storage/emulated/0' not a directory