Based on common file naming patterns, here are the most likely explanations for what you are seeing:
: Some streaming services or digital rights management (DRM) systems rename files with unique strings (like _m_smp4 ) to prevent direct playback or unauthorized sharing outside of their native app. _m_smp4
Could you tell me or what software you were using when it appeared? This will help me give you a much more specific answer. Based on common file naming patterns, here are
: If this appeared after using a specific downloader or editing tool, check that software's "Export" or "Save" settings to see if the process was interrupted. Based on common file naming patterns