• Registered: 2020-07-02
  • Posts: 78

Topic: MT5 Strategy Tester Inputs Tab is Blank

Popov wrote:

Hello, Traders,

A new version of the Expert Advisor Plus.mq5 v6.8 has been uploaded.

Hi Popov!

I discovered a small bug regarding MT5 backtester. The grid-generated EA compiles successfully with no errors, but MT5 Strategy Tester Inputs tab is blank. The issue appears when custom enum declarations are placed between input declarations. Moving all enum declarations above the first input fixed the problem and then I could backtest in MT5. It compiled fine in MetaEditor either way though, the editor didn't catch or flag it, but the backtester is more strict about the order I guess.

  • Registered: 2020-07-02
  • Posts: 78

Re: MT5 Strategy Tester Inputs Tab is Blank

You know, it might also be the length of the filename that was a problem too and not the order, because I just had another one with the same problem, and changing the order in the code didn't fix it, but shortening the filename did.

  • Popov
  • Popov
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  • From: Bulgaria
  • Registered: 2006-11-30
  • Posts: 8,280

Re: MT5 Strategy Tester Inputs Tab is Blank

There are similar reports in the MT forums.
The issue is most likely related to the visual rendering of the MT Tester.
I doubt it has anything to do with the MQL code or the filename itself.

Popov's Website

  • Registered: 2020-07-02
  • Posts: 78

Re: MT5 Strategy Tester Inputs Tab is Blank

It definitely solved it when I changed order in the code and shortened the filename. I'm not sure if it was one or both that fixed it both times yet.

  • Popov
  • Popov
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  • Registered: 2006-11-30
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Re: MT5 Strategy Tester Inputs Tab is Blank

Enumeration declarations exist only in the source code.
Once the file is compiled, the enumerations disappear. The enumeration values are replaced with constant integer numbers in the compiled expert.

However, MetaTrader creates something (probably a HashMap) from the comments on the enum values because we see them in the options.

You can easily prove whether this is the real reason for the issue you are observing. Move the declarations back and forth, compile the expert, and see if the Tester is rendered correctly. If you find something, report it to MetaQuotes. (I have reported issues to them before, and neither received a response nor were the issues fixed.)

I also don't think the filename length can cause such issues.

The most probable reason for the problem is misbehavior of the C++ libs MetaTrader uses, the display driver, monitor sharing, or desktop scaling.

Check for error messages in the Expert or the Journal tabs. If there is an issue, I'll fix it.

Popov's Website

6 Reply by aaronpriest (edited by aaronpriest 2026-06-16 02:46:16)

  • Registered: 2020-07-02
  • Posts: 78

Re: MT5 Strategy Tester Inputs Tab is Blank

It's most definitely the length of the filename, I just tested it three times to verify it. So it's not the code, but a Metatrader bug. You have to delete the \Tester folder or you might not notice, because it will stubbornly load the settings of the last tested ex5 instead, so you might not even notice if a previously tested EA had similar settings. But if you delete the \Tester folder first and then open MT5 you'll get a blank page instead of old cached settings from the previous test if the filename is too long. I'm not sure exactly how many characters is the limit yet, but "BOT_EA_Farming_GRID_BASE_AUDCAD_M15_ORIG1740201819_EAS1740201819.mq5" is too long and renaming it to "BOT_EA_Farming_GRID_BASE_AUDCAD_M15_ORIG.mq5" and recompiling works. So, we'll just keep our filenames shorter in the future. ;-)

It was just a coincidence that I had renamed the file to something short like "test" when I had rearranged enums to be first before inputs in the code trying to figure out what was breaking MT5.

I'd report it on MetaQuotes forum, but I have bugs going back more than 5 years now that they've refused to acknowledge, respond to, or fix, hahaha!

  • Popov
  • Popov
  • Lead Developer
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  • From: Bulgaria
  • Registered: 2006-11-30
  • Posts: 8,280

Re: MT5 Strategy Tester Inputs Tab is Blank

Sorry, I was thinking you meant the exported filename is too long.

Historically, the Windows file path was limited to 260 characters (including the drive letter and the directories).
This is probably a safe limit.

Very good observation!

Popov's Website