I have done the Tools > Options > max bar history is set to 250000 and max bars in chart is set to 5000.
I have also tried to refresh the chart, and even deleting the history file for the time frame of the particular pair.
I also sometimes have gaps in my charts that also don't fill in, when I refresh. I've reinstalled MT4 a few times, but keep having the problem eventually pop up again.
I've searched and can't find any solution.
Deleting the history files is effective only if the terminal is down. It should fix the gaps.