Are you talking about these (attached)?

This is where ProSeries tracks the last 5 years worth of 1231 losses.  The short answer, it's an IRS anti-abuse rule that prevents you from using losses from one year to offset regular income at regular tax rates and then using gains in any of the five subsequent years to get capital gains tax rates.  Future gains are taxed at ordinary tax rates to the extent of your 1231 losses in the five preceding years.  This is where ProSeries tracks those amounts.  If that's what you're asking about, don't delete them, they may be necessary in order to prepare an accurate return in the future.