MT5 · Runtime errors
MT5 4001 · Unexpected internal error | YI GOLD
ERR_INTERNAL_ERROR
Official meaning
Unexpected internal error
Possible causes · YI GOLD suggestions
Determine the cause from the official meaning, the triggering function and terminal logs.
Troubleshooting · YI GOLD suggestions
Inspect terminal logs and the failing function return value. Check inputs, array bounds, resources, connectivity and required permissions against the official description.