I am using IQFeed intraday data which I would like to convert into daily data, because the high and low of their daily data is not accurate (or any other source for that matter). The IQFeed intraday includes pre and post market trading in the data which wealthlab is incorporating into the daily data. This is ruins the accuracy of the daily data. Is it possible to stop this and use only regular trading hours?

My goal is essentially to create daily bars from intraday bars of regular trading hours.

Two words: Market Manager

Supported by IQFeed. Just set your custom Open and Close time for the market, define symbols, and apply changes.

Thanks Eugene this is exactly what I need. Will enabling this tool result in Wealthlab not downloading the data outside these hours, or does it just filter them out when backtesting? There is a large amount of unnecessary data downloading which takes quite a long time with intraday data.

It will just filter them out.

Pre/post market trading does not generate an enormous amount of unnecessary data. To speed things up, consider disabling on demand data update, downloading the data for your DataSet and just keeping it up to date (consumes less bandwidth).