Runtime Errors

The GetLastError() function return last error code, stored in _LastError predefined variable. This value can be reset using the ResetLastError() function. Error code constants defined at stderror.mqh file. To print text messages use ErrorDescription() function defined at stdlib.mqh file.

For convenience, trade errors are additionally listed in the Trade Server Return Codes section.

Runtime errors of mql4-program:

Code	ID	Description
0	ERR_NO_ERROR	No error returned
1	ERR_NO_RESULT	No error returned, but the result is unknown
2	ERR_COMMON_ERROR	Common error
3	ERR_INVALID_TRADE_PARAMETERS	Invalid trade parameters
4	ERR_SERVER_BUSY	Trade server is busy
5	ERR_OLD_VERSION	Old version of the client terminal
6	ERR_NO_CONNECTION	No connection with trade server
7	ERR_NOT_ENOUGH_RIGHTS	Not enough rights
8	ERR_TOO_FREQUENT_REQUESTS	Too frequent requests
9	ERR_MALFUNCTIONAL_TRADE	Malfunctional trade operation
64	ERR_ACCOUNT_DISABLED	Account disabled
65	ERR_INVALID_ACCOUNT	Invalid account
128	ERR_TRADE_TIMEOUT	Trade timeout
129	ERR_INVALID_PRICE	Invalid price
130	ERR_INVALID_STOPS	Invalid stops
131	ERR_INVALID_TRADE_VOLUME	Invalid trade volume
132	ERR_MARKET_CLOSED	Market is closed
133	ERR_TRADE_DISABLED	Trade is disabled
134	ERR_NOT_ENOUGH_MONEY	Not enough money
135	ERR_PRICE_CHANGED	Price changed
136	ERR_OFF_QUOTES	Off quotes
137	ERR_BROKER_BUSY	Broker is busy
138	ERR_REQUOTE	Requote
139	ERR_ORDER_LOCKED	Order is locked
140	ERR_LONG_POSITIONS_ONLY_ALLOWED	Buy orders only allowed
141	ERR_TOO_MANY_REQUESTS	Too many requests
145	ERR_TRADE_MODIFY_DENIED	Modification denied because order is too close to market
146	ERR_TRADE_CONTEXT_BUSY	Trade context is busy
147	ERR_TRADE_EXPIRATION_DENIED	Expirations are denied by broker
148	ERR_TRADE_TOO_MANY_ORDERS	The amount of open and pending orders has reached the limit set by the broker
149	ERR_TRADE_HEDGE_PROHIBITED	An attempt to open an order opposite to the existing one when hedging is disabled
150	ERR_TRADE_PROHIBITED_BY_FIFO	An attempt to close an order contravening the FIFO rule
4000	ERR_NO_MQLERROR	No error returned
4001	ERR_WRONG_FUNCTION_POINTER	Wrong function pointer
4002	ERR_ARRAY_INDEX_OUT_OF_RANGE	Array index is out of range
4003	ERR_NO_MEMORY_FOR_CALL_STACK	No memory for function call stack
4004	ERR_RECURSIVE_STACK_OVERFLOW	Recursive stack overflow
4005	ERR_NOT_ENOUGH_STACK_FOR_PARAM	Not enough stack for parameter
4006	ERR_NO_MEMORY_FOR_PARAM_STRING	No memory for parameter string
4007	ERR_NO_MEMORY_FOR_TEMP_STRING	No memory for temp string
4008	ERR_NOT_INITIALIZED_STRING	Not initialized string
4009	ERR_NOT_INITIALIZED_ARRAYSTRING	Not initialized string in array
4010	ERR_NO_MEMORY_FOR_ARRAYSTRING	No memory for array string
4011	ERR_TOO_LONG_STRING	Too long string
4012	ERR_REMAINDER_FROM_ZERO_DIVIDE	Remainder from zero divide
4013	ERR_ZERO_DIVIDE	Zero divide
4014	ERR_UNKNOWN_COMMAND	Unknown command
4015	ERR_WRONG_JUMP	Wrong jump (never generated error)
4016	ERR_NOT_INITIALIZED_ARRAY	Not initialized array
4017	ERR_DLL_CALLS_NOT_ALLOWED	DLL calls are not allowed
4018	ERR_CANNOT_LOAD_LIBRARY	Cannot load library
4019	ERR_CANNOT_CALL_FUNCTION	Cannot call function
4020	ERR_EXTERNAL_CALLS_NOT_ALLOWED	Expert function calls are not allowed
4021	ERR_NO_MEMORY_FOR_RETURNED_STR	Not enough memory for temp string returned from function
4022	ERR_SYSTEM_BUSY	System is busy (never generated error)
4023	ERR_DLLFUNC_CRITICALERROR	DLL-function call critical error
4024	ERR_INTERNAL_ERROR	Internal error
4025	ERR_OUT_OF_MEMORY	Out of memory
4026	ERR_INVALID_POINTER	Invalid pointer
4027	ERR_FORMAT_TOO_MANY_FORMATTERS	Too many formatters in the format function
4028	ERR_FORMAT_TOO_MANY_PARAMETERS	Parameters count exceeds formatters count
4029	ERR_ARRAY_INVALID	Invalid array
4030	ERR_CHART_NOREPLY	No reply from chart
4050	ERR_INVALID_FUNCTION_PARAMSCNT	Invalid function parameters count
4051	ERR_INVALID_FUNCTION_PARAMVALUE	Invalid function parameter value
4052	ERR_STRING_FUNCTION_INTERNAL	String function internal error
4053	ERR_SOME_ARRAY_ERROR	Some array error
4054	ERR_INCORRECT_SERIESARRAY_USING	Incorrect series array using
4055	ERR_CUSTOM_INDICATOR_ERROR	Custom indicator error
4056	ERR_INCOMPATIBLE_ARRAYS	Arrays are incompatible
4057	ERR_GLOBAL_VARIABLES_PROCESSING	Global variables processing error
4058	ERR_GLOBAL_VARIABLE_NOT_FOUND	Global variable not found
4059	ERR_FUNC_NOT_ALLOWED_IN_TESTING	Function is not allowed in testing mode
4060	ERR_FUNCTION_NOT_CONFIRMED	Function is not allowed for call
4061	ERR_SEND_MAIL_ERROR	Send mail error
4062	ERR_STRING_PARAMETER_EXPECTED	String parameter expected
4063	ERR_INTEGER_PARAMETER_EXPECTED	Integer parameter expected
4064	ERR_DOUBLE_PARAMETER_EXPECTED	Double parameter expected
4065	ERR_ARRAY_AS_PARAMETER_EXPECTED	Array as parameter expected
4066	ERR_HISTORY_WILL_UPDATED	Requested history data is in updating state
4067	ERR_TRADE_ERROR	Internal trade error
4068	ERR_RESOURCE_NOT_FOUND	Resource not found
4069	ERR_RESOURCE_NOT_SUPPORTED	Resource not supported
4070	ERR_RESOURCE_DUPLICATED	Duplicate resource
4071	ERR_INDICATOR_CANNOT_INIT	Custom indicator cannot initialize
4072	ERR_INDICATOR_CANNOT_LOAD	Cannot load custom indicator
4073	ERR_NO_HISTORY_DATA	No history data
4074	ERR_NO_MEMORY_FOR_HISTORY	No memory for history data
4075	ERR_NO_MEMORY_FOR_INDICATOR	Not enough memory for indicator calculation
4099	ERR_END_OF_FILE	End of file
4100	ERR_SOME_FILE_ERROR	Some file error
4101	ERR_WRONG_FILE_NAME	Wrong file name
4102	ERR_TOO_MANY_OPENED_FILES	Too many opened files
4103	ERR_CANNOT_OPEN_FILE	Cannot open file
4104	ERR_INCOMPATIBLE_FILEACCESS	Incompatible access to a file
4105	ERR_NO_ORDER_SELECTED	No order selected
4106	ERR_UNKNOWN_SYMBOL	Unknown symbol
4107	ERR_INVALID_PRICE_PARAM	Invalid price
4108	ERR_INVALID_TICKET	Invalid ticket
4109	ERR_TRADE_NOT_ALLOWED	Trade is not allowed. Enable checkbox “Allow live trading” in the Expert Advisor properties
4110	ERR_LONGS_NOT_ALLOWED	Longs are not allowed. Check the Expert Advisor properties
4111	ERR_SHORTS_NOT_ALLOWED	Shorts are not allowed. Check the Expert Advisor properties
4112	ERR_TRADE_EXPERT_DISABLED_BY_SERVER	Automated trading by Expert Advisors/Scripts disabled by trade server
4200	ERR_OBJECT_ALREADY_EXISTS	Object already exists
4201	ERR_UNKNOWN_OBJECT_PROPERTY	Unknown object property
4202	ERR_OBJECT_DOES_NOT_EXIST	Object does not exist
4203	ERR_UNKNOWN_OBJECT_TYPE	Unknown object type
4204	ERR_NO_OBJECT_NAME	No object name
4205	ERR_OBJECT_COORDINATES_ERROR	Object coordinates error
4206	ERR_NO_SPECIFIED_SUBWINDOW	No specified subwindow
4207	ERR_SOME_OBJECT_ERROR	Graphical object error
4210	ERR_CHART_PROP_INVALID	Unknown chart property
4211	ERR_CHART_NOT_FOUND	Chart not found
4212	ERR_CHARTWINDOW_NOT_FOUND	Chart subwindow not found
4213	ERR_CHARTINDICATOR_NOT_FOUND	Chart indicator not found
4220	ERR_SYMBOL_SELECT	Symbol select error
4250	ERR_NOTIFICATION_ERROR	Notification error
4251	ERR_NOTIFICATION_PARAMETER	Notification parameter error
4252	ERR_NOTIFICATION_SETTINGS	Notifications disabled
4253	ERR_NOTIFICATION_TOO_FREQUENT	Notification send too frequent
4260	ERR_FTP_NOSERVER	FTP server is not specified
4261	ERR_FTP_NOLOGIN	FTP login is not specified
4262	ERR_FTP_CONNECT_FAILED	FTP connection failed
4263	ERR_FTP_CLOSED	FTP connection closed
4264	ERR_FTP_CHANGEDIR	FTP path not found on server
4265	ERR_FTP_FILE_ERROR	File not found in the MQL4\Files directory to send on FTP server
4266	ERR_FTP_ERROR	Common error during FTP data transmission
5001	ERR_FILE_TOO_MANY_OPENED	Too many opened files
5002	ERR_FILE_WRONG_FILENAME	Wrong file name
5003	ERR_FILE_TOO_LONG_FILENAME	Too long file name
5004	ERR_FILE_CANNOT_OPEN	Cannot open file
5005	ERR_FILE_BUFFER_ALLOCATION_ERROR	Text file buffer allocation error
5006	ERR_FILE_CANNOT_DELETE	Cannot delete file
5007	ERR_FILE_INVALID_HANDLE	Invalid file handle (file closed or was not opened)
5008	ERR_FILE_WRONG_HANDLE	Wrong file handle (handle index is out of handle table)
5009	ERR_FILE_NOT_TOWRITE	File must be opened with FILE_WRITE flag
5010	ERR_FILE_NOT_TOREAD	File must be opened with FILE_READ flag
5011	ERR_FILE_NOT_BIN	File must be opened with FILE_BIN flag
5012	ERR_FILE_NOT_TXT	File must be opened with FILE_TXT flag
5013	ERR_FILE_NOT_TXTORCSV	File must be opened with FILE_TXT or FILE_CSV flag
5014	ERR_FILE_NOT_CSV	File must be opened with FILE_CSV flag
5015	ERR_FILE_READ_ERROR	File read error
5016	ERR_FILE_WRITE_ERROR	File write error
5017	ERR_FILE_BIN_STRINGSIZE	String size must be specified for binary file
5018	ERR_FILE_INCOMPATIBLE	Incompatible file (for string arrays-TXT, for others-BIN)
5019	ERR_FILE_IS_DIRECTORY	File is directory not file
5020	ERR_FILE_NOT_EXIST	File does not exist
5021	ERR_FILE_CANNOT_REWRITE	File cannot be rewritten
5022	ERR_FILE_WRONG_DIRECTORYNAME	Wrong directory name
5023	ERR_FILE_DIRECTORY_NOT_EXIST	Directory does not exist
5024	ERR_FILE_NOT_DIRECTORY	Specified file is not directory
5025	ERR_FILE_CANNOT_DELETE_DIRECTORY	Cannot delete directory
5026	ERR_FILE_CANNOT_CLEAN_DIRECTORY	Cannot clean directory
5027	ERR_FILE_ARRAYRESIZE_ERROR	Array resize error
5028	ERR_FILE_STRINGRESIZE_ERROR	String resize error
5029	ERR_FILE_STRUCT_WITH_OBJECTS	Structure contains strings or dynamic arrays
5200	ERR_WEBREQUEST_INVALID_ADDRESS	Invalid URL
5201	ERR_WEBREQUEST_CONNECT_FAILED	Failed to connect to specified URL
5202	ERR_WEBREQUEST_TIMEOUT	Timeout exceeded
5203	ERR_WEBREQUEST_REQUEST_FAILED	HTTP request failed
	User errors
65536	ERR_USER_ERROR_FIRST	User defined errors start with this code

Last updated on 2026-06-26

Compilation Errors