Depending on how you’re doing this you may need to save them somewhere else.
The uasset needs to be in the project folder > Content > “name of folder here”
Make sure that the uasset file is located in the project that you’re opening. If it’s not it will not be present in the project.
If you want this to be part of a new project that is created you can drop this into the Engine folder where your engine is installed. This way it will be included with any “starter content” that you click to include with any newly created projects.
File Path for folder: X:/ Program Files / Unreal Engine / (engine version you want this work with. ie. 4.2) / Samples / Starter Content / Content / (Create a folder here or find one that best fits with it and drop it in)
I’m not sure if using the assets from a newer build will work with an older one. If you’re still having problems beyond this let me know and I’ll test it out.
The .uasset files were released a while ago ; they should be of an older build than 4.2
I put them into: “myproject/content/free meshes”
It is the right project I’m opening, I only have one
Edit: Fixed ; there was a space in the folder name sry