4.9 Conversion, external reference bug

any ideas why my player character was disappear ? my ue 4.9 has the substance plugin installed and now when i try to oopen the converted project the engine told me if i want to download the substance plugin from the marketplace (that plugin is not available for 4.10) can the missing substance plugin affect my game causing my player character disappear ?

my two 4.9 projects converted from 4.9 to 4.10 has the same issue.

need help, please.