MQL4 ERR_NO_MEMORY_FOR_HISTORY
MQL4 error 4074 no memory for history data maps to ERR_NO_MEMORY_FOR_HISTORY: not enough memory for history data. The terminal could not allocate enough memory for the requested historical series data. Capture GetLastError immediately after the failed call, correct the cause, and retry only when the condition can change.
Open the Coding Agent, then choose MQL4 from the language menu.
#property strict
#property script_show_inputs
input int Period = 14;
void OnStart()
{
if(Period < 1 || Bars <= Period)
{
Print("Invalid period or insufficient history: ", Period);
return;
}
ResetLastError();
double value = iMA(NULL, 0, Period, 0, MODE_SMA, PRICE_CLOSE, 1);
int error_code = GetLastError();
if(error_code != 0)
{
Print("iMA failed. error=", error_code);
return;
}
Print("SMA: ", DoubleToString(value, Digits));
}The official MQL4 runtime table names error 4074 ERR_NO_MEMORY_FOR_HISTORY and defines it as “not enough memory for history data.” The terminal could not allocate enough memory for the requested historical series data.
The error number is evidence about one failed call, not a diagnosis of the whole EA. Read the API sentinel first, then call GetLastError immediately because that function returns the current _LastError value and resets it.
Start with the inputs and external state that existed at the failure point. A later log entry or a successful call can overwrite the useful context.
Reduce memory demand before retrying. Repeating the same large history request can make the terminal less stable.
Keep the original trading and risk rules intact. A workaround that widens stops, increases volume, changes an account setting, or ignores a failed return value can hide the symptom while changing the system.
| Check | Action |
|---|---|
| The program requests many symbols, timeframes, bars, or indicator instances | Request only the symbols, timeframes, and bar range used by the calculation. |
| Large arrays duplicate history that MT4 already stores | Reuse buffers and avoid copying full history when a bounded window is enough. |
| A loop repeatedly loads history without releasing or reusing data | Cache successful results and stop repeated history-loading loops. |
| The terminal runs under constrained memory with many charts open | Reproduce with fewer charts or indicators and record the terminal build and memory state. |
The script bounds its period and checks available bars before requesting one indicator value. Apply the same bounded-window rule to multi-symbol history code.
The example improves validation and logging. It does not prove the operation will be accepted by a broker or behave safely in live trading.
#property strict
#property script_show_inputs
input int Period = 14;
void OnStart()
{
if(Period < 1 || Bars <= Period)
{
Print("Invalid period or insufficient history: ", Period);
return;
}
ResetLastError();
double value = iMA(NULL, 0, Period, 0, MODE_SMA, PRICE_CLOSE, 1);
int error_code = GetLastError();
if(error_code != 0)
{
Print("iMA failed. error=", error_code);
return;
}
Print("SMA: ", DoubleToString(value, Digits));
}Pineify can generate or revise one self-contained .mq4 file with MQL4-specific reference context. Its independent static checker returns MetaEditor diagnostics so you can repair source issues before testing in your own MT4 environment.
Open MQL4 Coding AgentStatic diagnostics do not prove runtime behavior, backtest results, broker compatibility, or live-trading safety.
Check the API return value before interpreting an error number from the log.
Call GetLastError immediately and record error 4074, symbol, prices, volume, ticket, and terminal state relevant to the operation.
Request only the symbols, timeframes, and bar range used by the calculation.
Compile the revised source, then test with the same MT4 build, broker, symbol, account permissions, and market state.
ERR_NO_MEMORY_FOR_HISTORY means not enough memory for history data. The code should still identify which API returned failure and log the inputs used for that call.
The program requests many symbols, timeframes, bars, or indicator instances Large arrays duplicate history that MT4 already stores A loop repeatedly loads history without releasing or reusing data The terminal runs under constrained memory with many charts open
Reduce memory demand before retrying. Repeating the same large history request can make the terminal less stable.
It reports the current _LastError value and resets it. Other operations can change the error state, so a delayed read may describe the wrong call.
Pineify can revise a self-contained .mq4 file, add validation and error logging, and return static MetaEditor diagnostics. It cannot prove broker acceptance, account permissions, market availability, or live execution.
Last verified against the linked official references on . Compile and test the final source in the MetaTrader 4 build, broker, symbol, and account environment you plan to use.
Define the requirement, inspect the generated source, repair diagnostics, and test the behavior in your own MT4 environment.
Open Coding Agent