MetaTrader 5 build 6257 automatically launches MetaEditor before user interaction

[Sindri Páll]

Hello MetaQuotes Technical Support,

We are developing a private read-only historical market-data research system using MetaTrader 5 build 5.0.0.6257 on Windows.

The terminal is launched using `/portable` and a private configuration.

Trading permissions are disabled, and the existing MQL5 Services are configured not to start automatically.

During two independently controlled startup attempts, `terminal64.exe` unexpectedly created a child process running `MetaEditor64.exe`.

This occurred before we opened MetaEditor, used the AI Assistant, or manually started a Service.

The process identities and parent-child relationships were verified.

The latest attempt recorded MetaEditor appearing approximately 3.34 seconds after terminal creation.

Our process-isolation controls correctly rejected the unexpected child and terminated the isolated process tree.

We observed that the private configuration has MetaTrader and MetaEditor MCP endpoints enabled. However, we do not know whether the separate option "Start MetaEditor while Assistant is active" is enabled.

Could you clarify:

1. What could cause MetaEditor to launch automatically during terminal startup on build 6257?

2. Can a restored AI Assistant state or MCP connection trigger MetaEditor without an explicit user action?

3. Is there an officially supported method to inspect or disable "Start MetaEditor while Assistant is active" BEFORE launching MT5?

4. Is there a documented configuration key, command-line argument, API or installation-local startup option for preventing this behavior?

5. Can we prevent optional MetaEditor startup while continuing to use an existing compiled MQL5 Service through Navigator?

6. If the relevant option is stored persistently, where is it stored, how is its precedence determined, and how can it be safely reverted?

We need a solution confined to this private terminal installation without modifying other terminals, trading permissions or compiled Service binaries.

Thank you.

[Jevon Naldo Yoshield]

A few things to check: (1) MQL5 Services can be configured to start with the terminal — even if you believe they are disabled, verify in Tools > Options > Expert Advisors that 'Allow automated trading' and service auto-start are off, and check the terminal's log for 'service started' entries. (2) The AI Assistant / Copilot integration can spawn MetaEditor for code suggestions; disable it under Tools > Options > Community. (3) A script or indicator with OnInit that calls ShellExecute or ExpertRemove can trigger editor launch. (4) Check if there is a .bat or scheduled task launching MetaEditor. The 3.34s delay suggests a service or scheduled component rather than a direct user action. The terminal log (Experts tab) usually records the trigger.

[Sindri Páll]

Thank you for the suggestions.

We investigated the proposed startup causes without launching the private MT5 terminal again.

Our findings:

- All three private MQL5 Services are configured with automatic startup disabled.

- Trading and DLL execution are disabled in the private startup configuration.

- The retained logs contain no relevant Service, EA, script or AI Assistant events around the unexpected MetaEditor launches. This does not rule out unlogged activity.

- We found no direct MetaTrader/MetaEditor launch references among 204 inspected scheduled tasks or the reviewed Windows startup entries/scripts.

- Our launcher starts only terminal64.exe.

MetaEditor64.exe has appeared repeatedly as a direct child of terminal64.exe, before operator Service activation or Options inspection.

We use MetaTrader 5 build 5.0.0.6257 on Windows, in a private portable installation.

One unverified possibility is the AI Assistant option "Start MetaEditor while Assistant is active". MCP.MetaEditor and MCP.MetaTrader are enabled, but this does not establish the separate checkbox's state. Its effective value and the actual launch trigger remain UNKNOWN. MetaEditor starts before we can reach the Options dialog; we have not established a supported offline way to inspect the setting.

Could a MetaQuotes developer or someone familiar with build 6257 clarify:

1. Where is this specific checkbox's state persisted?

2. Is there a documented, supported method to inspect or disable it while MT5 is stopped?

3. Could restored AI Assistant state or MCP integration automatically launch MetaEditor during terminal startup?

4. Is there an official launch argument, API or configuration method to suppress optional MetaEditor startup?

5. Can MetaEditor auto-start be disabled while preserving execution of existing compiled MQL5 Services?

We need an installation-local solution that leaves our other terminals and trading permissions unchanged. We are not looking for undocumented registry or INI modifications.

Any official build-specific guidance would be greatly appreciated.

[Stanislav Korotky]

If the terminal detects that some of executable codes (ex5) are out of date or source codes need to be recompiled (I can't tell you specific conditions for that), it can force compilation which implies the start-up of metaeditor behind the scenes.

[Ryan L Johnson]

Sindri Páll #:
Is there an official launch argument, API or configuration method to suppress optional MetaEditor startup?

Not an "official launch argument" but there is an official "Launch" Help page:

If the platform/MetaEditor has previously worked in the main mode, no files from the user directory are transferred to the installation one after launching in the Portable mode. Only new data are saved in the installation directory.

MetaEditor launch in an incorrect mode may cause the absence of files in the Navigator window. When you start in normal mode, the data is requested from the folder where the executable file is stored, and in the guest mode, they are requested from the user's system folder. (emphasis added).

As the Navigator window appears to call MetaEditor, I'd be interested to know what happens if you close the Navigator window and save that configuration as the Default Profile in MT5. This a reverse engineered hack of sorts.

[Sindri Páll]

Stanislav, thank you. We checked the recompilation possibility without restarting the private terminal.

For MT5 build 6257 on Windows:

- The journal records a full recompilation of 131 files on October 15, before three successful historical tick-collection batches.

- We inspected 149 MQ5 sources and 134 EX5 binaries. Every binary has a corresponding source; no paired source or resolved include dependency has a newer timestamp.

- The 15 source-only files are bundled Scripts/UnitTests. We have not established that they trigger anything.

- No contemporaneous compilation entries establish recompilation during the later failed starts. Early termination may limit logging.

- Terminal and MetaEditor executable hashes still match the earlier successful installation. All private Service auto-starts are disabled.

MetaEditor nevertheless appeared as a direct terminal child before operator interaction. The trigger remains UNKNOWN.

Could you or MetaQuotes clarify:

1. What exact conditions make build 6257 spawn MetaEditor automatically at terminal startup?

2. Can this happen when existing source/binary pairs appear up to date, including their dependencies?

3. Can a previous full-recompilation state cause later MetaEditor launches?

4. Do bundled Scripts/UnitTests without EX5 files participate in startup-compilation checks?

5. Is there a documented way to identify a pending compilation request while the terminal is stopped?

6. Is there a supported installation-local way to prevent optional MetaEditor startup while preserving existing compiled MQL5 Services?

We need to leave other terminals and trading permissions unchanged. Thank you.

[Stanislav Korotky]

One of the reasons for the terminal to decide to recompile example source codes (which are installed along with the terminal) is some changes in MQL5 compiler, which should produce altered ex5 binary codes. I'm not from MQ, so I can't tell you at which moment such recompilation may become required for your custom source codes. Usually, older ex5 binaries are handled normally for quite some time (successive release builds) but eventually the platform requires their recompilation.

Since you said you found in the log 131 records about files recompilation, then you can deduce what kind of the files that was.