I just found the following thread with the discussion (MT5 but same error 4):
Initialization Error 4 Windows 10 HomeYou are missing trading opportunities:
- Free trading apps
- Over 8,000 signals for copying
- Economic news for exploring financial markets
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Since trying to download and run the new Windows 10 upgrade and failing, I now cannot run my MT4's from my Desktop without it coming up with Initialisation Error 4
Help please