MT4 error 4200: Object already exists
Give each object its own name.
Updated 24 October 2026. Runs in your browser; nothing you type is uploaded.
The number after "error" in MT4's Experts or Journal tab. 161 codes, as MQL4's reference words them.
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What MQL4 says
4200ERR_OBJECT_ALREADY_EXISTS- Object already exists
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
ObjectCreate() was given a name already used on that chart. MQL4's ObjectCreate page: the name must be unique within a chart, including its subwindows.
How to fix it
Give each object a name no other object on the chart has. Check ObjectFind(name) before creating: if the object exists, move or restyle it instead, or delete it first with ObjectDelete(); for one object per bar, put the bar's time in the name.
Source: MQL4 Reference: ObjectCreate. No MQL4 code is shown because none here was compiled; adapt the steps to your EA.
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 5004: Cannot open file
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