MT4 error 5004: Cannot open file

What MQL4 says

5004 ERR_FILE_CANNOT_OPEN

Cannot open file

From MQL4's table of error codes, read 24 October 2026. An Expert Advisor reads it with GetLastError() after a call fails; the Experts and Journal tabs print what the EA logs.

What causes it

FileOpen() couldn't open the file. MQL4 keeps files in a sandbox: the MQL4\Files folder of the terminal's data folder (Tester\Files when testing), or the folder shared by all MT4 terminals with FILE_COMMON. A path outside it can't be opened.

How to fix it

Open files inside MQL4\Files only. Pass a name relative to it (no drive letter or full path), add FILE_COMMON for a file several terminals share, and check for INVALID_HANDLE, which FileOpen() returns when it fails.

Source: MQL4 Reference: FileOpen. No MQL4 code is shown because none here was compiled; adapt the steps to your EA.

The same error in MT5

MT5 gives it its own runtime error code: MT5 error 5004: File opening error.

Other MT4 errors

• MT4 error 0: No error returned
• MT4 error 1: No error returned, but the result is unknown
• MT4 error 2: Common error
• MT4 error 3: Invalid trade parameters
• MT4 error 130: Invalid stops
• MT4 error 131: Invalid trade volume
• MT4 error 132: Market is closed
• MT4 error 133: Trade is disabled
• MT4 error 134: Not enough money
• MT4 error 136: Off quotes
• MT4 error 4051: Invalid function parameter value
• MT4 error 4107: Invalid price
• MT4 error 4111: Shorts are not allowed
• MT4 error 4112: Automated trading by Expert Advisors/Scripts disabled by trade server
• MT4 error 4200: Object already exists