MML Data Bridge – Common Issues and Resolves – Trading Systems – 26 December 2025

This doc addresses the most typical points customers encounter when establishing and utilizing MML Knowledge Bridge, together with step-by-step options

3. MML Knowledge Bridge: Can not open binary file (Error: 5002)

• Program quits unexpectedly
• EA fails to initialize
• Binary file entry errors throughout backtesting or optimization

• Binary file would not exist (CSV hasn’t been transformed to binary but)
• File is locked by one other course of or utility
• File path is inaccurate or inaccessible
• Inadequate file permissions

1. Guarantee CSV information are processed first – run EA as soon as to generate binary information earlier than backtesting
2. Shut another functions that could be accessing the information (Excel, textual content editors, and so on.)
3. Confirm binary information exist in CommonFiles[EA_Name] listing
4. Restart MetaTrader 5 if information seem locked
5. If binary file is lacking, delete config file and let MML Knowledge Bridge regenerate it

• Binary file header accommodates invalid document dimension. File is corrupted, empty, or was created incorrectly

• Delete the corrupted binary file from CommonFiles[EA_Name] listing
• Replace the CSV file (make a small change and save) to set off regeneration
• Or delete the binary file and restart EA – it should regenerate routinely
• Confirm CSV file has legitimate knowledge rows earlier than regeneration

• Numbers handled as textual content
• Dates not acknowledged
• Incorrect knowledge sorts in schema

• If a cell accommodates characters aside from INTS or DOUBLES, the entire column will probably be handled as CHARS

1. Test for blended knowledge sorts in similar column
2. Delete binaries and rerun to regenerate a brand new schema
3. Guarantee all values in a numeric column are numbers
4. Take away any textual content, symbols, or formatting from numeric columns

• Anticipated datetime column reveals up as Char[] in schema
• Time-based knowledge comparability fails
• Program will not run or produces incorrect outcomes
• Knowledge seems at flawed occasions in again tester

Root Trigger:

• DateTime column accommodates non-ISO 8601 format knowledge
• Blended knowledge sorts in datetime column
• Lacking timezone data in datetime values
• Invalid datetime format inflicting schema to categorise as textual content

1. Use correct ISO 8601 format – YYYY-MM-DDThh:mm:ssZ or YYYY-MM-DDThh:mm:ss±hh:mm. Instance: 2024-07-30T16:00:00Z
2. Guarantee timezone data – all datetime values should have timezone
3. Regenerate schema by deleting binary
4. Clear datetime knowledge – take away any non-standard codecs

7. MML Knowledge Bridge: Can not open configuration file

Error Messages:

• MML Knowledge Bridge: Can not open configuration file ‘%s’ (Error: %d)
• MML Knowledge Bridge: Anticipated location: Widespread Filespercents

• Configuration file is lacking, has incorrect path, or lacks learn permissions

1. Confirm config file exists in Widespread Information listing
2. Test file path matches EA identify folder construction
3. Confirm file isn’t locked by one other course of
4. Test file encoding is ANSI/textual content
5. Navigate to the Widespread Information listing proven within the error message

8. MML Knowledge Bridge: Configuration file lacking [Settings] header. Please examine your config file format

Root Trigger:

• Config file format is invalid or corrupted. The primary line have to be [Settings]

1. Guarantee first line is precisely [Settings] (case-insensitive)
2. Test for additional areas or characters
3. Confirm file encoding is ANSI/textual content
4. Guarantee correct line endings

9. MML Knowledge Bridge: Created new config file. Please add enter information and rerun

Root Trigger:

• Config file was simply created and desires file entries

1. Open config file in textual content editor
2. Add file entries: File1 = your_data.csv
3. Save config file
4. Restart EA

10. MML Knowledge Bridge: File has invalid extension. Solely .csv and .tsv information are supported

Root Trigger:

• File listed in config has an unsupported file extension

1. Guarantee file extension is precisely .csv or .tsv (case-insensitive)
2. Rename file if it has a unique extension
3. Replace config file with appropriate filename together with extension

11. MML Knowledge Bridge: The next file(s) listed in configuration weren’t discovered within the Widespread Information listing

Root Trigger:

• File is almost definitely misspelled or not within the appropriate listing

1. Test file spelling and ensure to incorporate file extension (.csv/.tsv) within the filename (spelling isn’t case delicate)
2. Use widespread information listing: C:Customers[YourUsername]AppDataRoamingMetaQuotesTerminalCommonFiles
3. Information ought to be positioned straight in CommonFiles (not in subfolders)
4. Confirm file exists earlier than including to config

12. MML Knowledge Bridge: No legitimate information present in configuration

Root Trigger:

• Config file has no legitimate file entries or all entries are invalid

1. Add file entries in format: File1 = your_data.csv
2. Guarantee information exist and are readable
3. Confirm file extensions are .csv or .tsv
4. Test information are in Widespread Information listing

• MML Knowledge Bridge: File ‘%s’ not present in configuration
• MML Knowledge Bridge: Please guarantee file(s) are within the Widespread Information listing and listed in your config file
• MML Knowledge Bridge: To repair: Add ‘FileN = filename.csv’ to your config file and restart EA
• MML Knowledge Bridge: EA will probably be eliminated attributable to configuration error

• Code requests a file not listed within the configuration. This happens when your EA code calls getRecordBytes_internal() with a filename that is not within the config file

1. Test file location – have to be in Widespread Information listing
2. Confirm filename in config file matches precisely (case-insensitive)
3. Add file to config utilizing format: FileN = filename.csv
4. Restart EA after updating config

14. MML Knowledge Bridge: Warning – CSV file ‘%s’ accommodates no knowledge rows. File should have at the very least one knowledge row after the header

Root Trigger:

• CSV file has a header row however no knowledge rows. Schema can’t be generated with out knowledge

Resolution:

1. Guarantee CSV file has at the very least one knowledge row after the header
2. Test that knowledge rows are usually not empty or whitespace-only
3. Confirm file was saved accurately
4. Add pattern knowledge rows to check the file format

15. MML Knowledge Bridge: ISO-8601 format error in ‘%s’ at row %d: ‘%s’. Anticipated format: YYYY-MM-DDThh:mm:ssZ or YYYY-MM-DDThh:mm:ss±hh:mm

Root Trigger:

• Schema detection failed. File has no header row, no knowledge rows, invalid format, or inconsistent column counts

1. Guarantee file has a legitimate header row with column names
2. Confirm file has at the very least one knowledge row
3. Test that each one rows have constant column counts
4. Confirm file encoding is appropriate (ANSI/textual content)
5. Guarantee correct delimiter utilization (single comma for CSV, single tab for TSV)

16. MML Knowledge Bridge: ISO-8601 format error in ‘%s’ at row %d: ‘%s’. Anticipated format: YYYY-MM-DDThh:mm:ssZ or YYYY-MM-DDThh:mm:ss±hh:mm

Root Trigger:

• DateTime worth would not match strict ISO-8601 format throughout CSV export. The worth proven didn’t parse

1. Use actual format: YYYY-MM-DDThh:mm:ssZ (UTC) or YYYY-MM-DDThh:mm:ss±hh:mm (with offset)
2. Guarantee ‘T’ separator between date and time (uppercase or lowercase each accepted)
3. Embody timezone: ‘Z’ for UTC or ±hh:mm for offset (e.g., -05:00 or +02:00)
4. Confirm all digits are current (no lacking zeros)
5. Instance: 2024-07-30T16:00:00Z or 2024-07-30T16:00:00-05:00

17. MML Knowledge Bridge: Warning – Row %d in ‘%s’ has %d columns, anticipated %d. Lacking columns will probably be padded with empty values

Root Trigger:

• CSV row has completely different column rely than detected schema throughout export. Lacking columns will probably be crammed with empty/default values

1. Guarantee all CSV rows have the identical variety of columns because the header
2. Test for lacking delimiters in knowledge rows
3. Confirm CSV file format is constant all through
4. Add lacking columns or take away additional columns to match header

18. MML Knowledge Bridge: Schema Mismatch – Column. File ‘%s’: Saved schema has %d cols, final line has %d cols

Root Trigger:

• Knowledge appended to a file doesn’t match the schema generated from again exams. New CSV knowledge row has completely different column rely than saved schema.

1. Preserve constant format as generated schema
2. Guarantee all CSV rows have similar variety of columns as the unique schema
3. Test for lacking or additional delimiters within the new knowledge row
4. Depend columns within the new row and match to schema

• Schema metadata corruption or mismatch. The saved schema definition would not match the precise knowledge row.

1. Delete binary file and config file
2. Restart EA to regenerate schema from CSV
3. Confirm CSV file has constant column rely
4. Test for schema corruption in config file

20. MML Knowledge Bridge: Schema Mismatch – Datatype. File ‘%s’, Column %d expects DateTime; bought ‘%s’

Root Trigger:

• Knowledge worth in DateTime column would not match ISO-8601 format. This happens when appending new knowledge in reside mode

1. Use correct ISO 8601 format with timezone: 2025-01-01T08:30:00-05:00
2. Guarantee format matches: YYYY-MM-DDThh:mm:ssZ or YYYY-MM-DDThh:mm:ss±hh:mm
3. Embody timezone data (required)
4. Instance: 2024-07-30T16:00:00Z or 2024-07-30T16:00:00-05:00

21. MML Knowledge Bridge: Schema Mismatch – Datatype. File ‘%s’, Column %d expects Int; bought ‘%s’

Root Trigger:

• Knowledge worth in Integer column accommodates non-numeric characters. This happens when appending new knowledge in reside mode

1. Guarantee worth is a legitimate integer (no decimals, no letters)
2. Take away any whitespace or formatting characters
3. Test for hidden characters or encoding points
4. Instance: 123 is legitimate, 123.0 or 123abc are invalid

22. MML Knowledge Bridge: Schema Mismatch – Datatype. File ‘%s’, Column %d expects Double; bought ‘%s’

Root Trigger:

• Knowledge worth in Double column can’t be parsed as a quantity. This happens when appending new knowledge in reside mode

1. Guarantee worth is numeric (integer or decimal)
2. Use interval (.) as decimal separator
3. Take away foreign money symbols or formatting
4. Instance: 123.45 is legitimate, $123.45 or 123,45 are invalid

23. MML Knowledge Bridge: Test config file for generated schemas and add to dataStructs.mqh to ingest knowledge

Root Trigger:

• Schema has been generated and must be added to your code

1. Open config file and find [Schema] part
2. Copy the DataType = … line for every file
3. Add corresponding struct definition to dataStructs.mqh
4. Guarantee struct subject order matches schema order
5. Restart EA

• CSV file was modified, and binary is being regenerated routinely

1. No motion wanted – that is automated
2. Look ahead to regeneration to finish
3. Confirm schema in config file if wanted

• First run – no metadata exists but (regular for brand new setup)

1. That is informational, not an error
2. EA will generate metadata and binaries on first run
3. Guarantee CSV information are correctly configured
4. Look ahead to initialization to finish

• New information have been added to the configuration.

1. No motion wanted – that is informational
2. Information will probably be processed routinely

• Information have been faraway from config and related binary information are being cleaned up.

1. No motion wanted – cleanup is automated

For extra assist, please contact the developer @rylanw337@gmail.com