Does a loss carry forward expire for a single person when they become married and file jointly?

What is LCF?  Capital loss carryover?

Yes. I was part owner (and single at that time) of a business which failed in 2011. I lost 100% of my investment in the business when the bank liquidated the collateral.

You will keep the Long-Term Capital loss carryforward from when you were single and carry it the joint return.

It does not, however, go on line 21.

You need to go to income area, 

then to investments

right after the stock, Mutual Funds, Bonds, Other you will see Capital Loss Carryover.

You will enter the Capital Loss carryover from the 2016 return as a positive number and then

It will be applied against other gains and your loss used up each year if no other gains are limited to $3,000 per year.