So the other day I asked a question of how to get an Entity NBTBase, which I found an alternative to. You can view my latest posts on my alternative in the link I provided. So, the main reason I asked there is so I have a way to Organize it better so when editing it, it isn't all jumbled up where it is hard to find everything if I have lots of data. I have not yet implemented into the Entity yet as I wanted to do a couple of steps before doing that when I came across something very annoying, which shows no error or nothing. When trying to append like a String Persistent Data Type to the Tag Container, it doesn't actually save it to the NBT file. Which again, I check using the Universal Minecraft Editor (Link provided). It creates the Tag Container quite find under BukkitValues in the player uuid-named compound (aka Tag). I also went a bit further in testing to see if it is for everything but Tag Container (For some odd reason) so I created a simple string and it worked quite find. Does anyone know what is going wrong, I know I am doing everything correctly. It worked with Entities, which I know from when I first tested using dataType TAG_CONTAINER. So why isn't it working for Player as well, makes no sense to me. A sample example code of the similar code I am working with should be in the post I provided. I'll try to constantly update on progress of further problems that originated from this and if I solved it on my own or not. Thanks in response.