Missing or incomplete historical data in Sierra Chart

What is causing it

The data has not been downloaded, your service does not supply that depth of history, or the local data files for that symbol are incomplete.

Why this happens

Sierra Chart keeps historical data in local files per symbol and fills them from your data service on request. A gap therefore means either the service would not supply it or the request was never made.

How far back a service will go is a commercial decision by that provider, which is why the same platform gives different history depending on what you are connected to.

The fix, step by step

1. Use the chart's option to download historical data for that symbol so the platform requests the range again.
2. Check how many days the chart is configured to load, since a low value produces a chart that looks short of history but is behaving correctly.
3. Confirm your data service actually provides historical data for that instrument, because some routing connections supply live data only.
4. Check whether the gap corresponds to a session break, a holiday or a period when you were not connected, all of which are legitimate.
5. For intraday data, expect the available history to be shorter than for daily data, as the storage requirement is far greater.
6. If a specific symbol is consistently wrong, redownloading its data is the appropriate fix, and it does not affect other symbols.

How to confirm it is fixed

Scroll back over the period you need and confirm bars are continuous, and spot-check a few against an independent source.

Stopping it happening again

Download the history you need for your regular symbols once, and re-download after any long absence or change of data service.