MetaTrader Data Folder
Also known as: MQL4 folder, MQL5 folder, terminal data folder, MetaTrader install folder
What is it?
The MetaTrader data folder is the per-installation directory where the terminal keeps everything you add to it: Expert Advisors, indicators, scripts, libraries, logs and the sandboxed files an EA is allowed to read and write. It is not the folder MetaTrader was installed into, and that catches people out constantly. The program lives in one place while its working data lives in a separate per-user directory with a long hashed name, reached from the terminal itself through File then Open Data Folder.
| Folder inside MQL4 / MQL5 | What belongs there | Symptom when it is wrong |
|---|---|---|
| Experts | Expert Advisors (your bots) | The EA never appears in the Navigator |
| Indicators | Custom indicators | The EA loads but plots nothing |
| Scripts | One-shot scripts you run manually | Nothing to double-click |
| Libraries | Shared DLLs and include files | The EA compiles but fails at runtime |
| Files | The EA's sandboxed read and write area | A file-based connector exchanges nothing |
| Logs | The terminal's own record | Where you look to find out why |
Inside it, MQL4 or MQL5 holds Experts for EAs, Indicators for custom indicators, Scripts, Libraries for shared DLLs and includes, Files for the EA's own sandboxed read and write access, and Logs for the terminal's record of what happened. Two consequences matter in practice. First, every installed terminal has its own data folder, so an EA copied into one is invisible to another, which is why a bot 'that will not appear in the Navigator' is almost always in the wrong folder or was added without restarting the terminal.
Second, an EA can only read and write inside that Files directory, so a connector exchanging data through a file must have both sides pointed at the same terminal's sandbox.
Why it matters: The data folder, not the install folder, is where MetaTrader looks for your EAs and indicators, which makes it the first place to check when a bot never appears.
An EA placed in the wrong data folder simply never runs, and a file-based connector pointed at a different terminal's sandbox silently exchanges nothing.
Real-world example
A trader running two MT5 terminals copied an EA into the first terminal's Experts folder and spent an evening debugging why the Navigator on the second terminal, the one actually connected to their live account, showed nothing.
How SignalBots handles it
The SignalBots MT4/MT5 connector installs into the data folder of the terminal you point it at, so signals reach the same platform your live account is logged into. See /risk-warning.
Pro tip
Always reach it through File then Open Data Folder in the terminal you actually trade on. Navigating there by hand is how files end up in a second installation's directory.
Common pitfalls
Copying an EA into the MetaTrader program directory instead of the data folder, where the terminal never looks for it and no error is ever shown.
Frequently asked questions
How do I find the data folder?
In the terminal, open the File menu and choose Open Data Folder. That guarantees you land in the directory belonging to that exact terminal, which is the only reliable way when more than one is installed.
Which subfolder does an EA go in?
MQL4/Experts on MetaTrader 4 and MQL5/Experts on MetaTrader 5. Custom indicators go in Indicators, one-shot scripts in Scripts, and shared DLLs or include files in Libraries.
Why does my EA not appear in the Navigator?
Almost always one of three things: it is in the wrong terminal's data folder, it is in the program directory rather than the data folder, or the terminal has not been restarted or the Navigator refreshed since the file was added.
What is the Files subfolder for?
It is the sandbox an EA is permitted to read and write in. MQL code cannot freely access the rest of the disk, so any connector or bridge that exchanges data through files must use this directory on both sides.
Do all my terminals share one data folder?
No. Each installation has its own, which is why an EA installed once does not appear everywhere. Portable-mode installations differ again, keeping their data inside the program directory instead.
