I have a character with three animations. Now i wanted to replace the FBX file because i have added a few more animations. So my first way was to simply drag the new FBX into the folder in the Project tab. No luck. The new file does not overwrite the old file. It imports the second file, and renames it to myfile 1. My next way leaded to the Explorer. Here i replaced the FBX file. Back in Unity my character stopped working: No jump animation found and the character has canJump enabled. Turning off animations. UnityEngine.Debug:Log(Object) ... Seems that the formerly created clips are not longer fitting to the new FBX. Which is curious, because all i did was adding a few more animations at the end. So what is the official way to replace a FBX file? Is it really necessary to build my character from scratch, and to adjust all the scripts to the new name then?