Certain ll* function calls, placed after an unconditional return in a function result in a "UThread injection failed" message. Not all functions do. Other code after a return causes a run-time error. Possibly related to SVC-1328. Examples (assume the same default state and state_entry event for each example): // Compile error test() { integer x; return; llSetColor(ZERO_VECTOR, ALL_SIDES); } default { state_entry() { test(); } } // Run-time error test() { integer x; return; x+=1; } // Compiles and runs with no problem test() { integer x; return; x = llListFindList(["a"], ["a"]); } // Compiles and runs with no problem test() { integer x; if (TRUE) return; x+=1; } The run-time error is [7:55] Donation Box: System.InvalidProgramException: Invalid IL code in LSL_0a331708_ce87_231f_2701_e40594700fa9:test (): IL_000d: nop at LSL_0a331708_ce87_231f_2701_e40594700fa9.defaultstate_entry () [0x00000] at LSL_0a331708_ce87_231f_2701_e40594700fa9defaultstate_entryFrame.ResumeVoid () [0x00000] at LindenLab.SecondLife.UThread.UThread.Run () [0x00000] at LindenLab.SecondLife.Script.Run (ScriptEvent evt) [0x00000]