I recorded the metahuman in low quality in which hair is not visible. I think that might be the reason this error is showing. I am not sure how to diagnose this error. I am a beginner so please excuse me.
I tried reading the other answers but couldn’t find a solution to this problem.
I haven’t made any edits in any of the blueprints or any settings.
I found that my spawned metahuman had a NiagaraComponent_0 spring system added, and if I deleted that from the spawned character and the track list, everything saved and worked fine. Hopefully this saves others some time.