40d:Reclaim fortress mode

To reclaim a fortress you can hit R on the fortress location choice screen. This will let you return to a previously lost or abandoned fortress.

If you prepare for the journey the Skills screen is different from standard Fortress Mode, showing your list of dwarves on the left and the list of skills on the right. The Skill list shows the total number of dwarves with that skill, not the skill level of the selected dwarf. The skills of the selected dwarf are shown highlighted in green. Each of your starting dwarves is allowed one military skill and one domestic profession, and if you do not like the randomly generated one (highlighted in green) for the selected dwarf, you can move the selector right and pick a new profession with Enter. The equipment screen is the same as standard Fortress mode.

Choosing specific professions will result in the dwarf having (no attribute) skill, general professions (Woodworker, Stoneworker, Ranger, Metalsmith, Jeweler, Craftsdwarf, Farmer, Engineer, Administrator) give novice skill level in each of the specialist skills in the same way as incoming migrants have them in dwarf fortress mode.

Upon arrival, you will see the items you left behind randomly flung about, buildings will be either destroyed or unclaimed, and all objects will be aged according to how long the place has been abandoned, so food will mostly be rotten or gone and dead bodies too will be rotting, bones or gone. All objects will also be forbidden. Forbidden is a good thing, at least if you're reclaiming a fortress that was conquered by beasties or invaders, as it keeps your dwarves from rushing off on hauling jobs to the middle of enemy infested nowhere.

Your dwarves start fully equipped with armor and weapons that match their military skill; it is therefore safe to not take extra axes with you. If your fortress had one or more anvils they will most likely also still be there, so you can ditch the anvil for, say, a horde of war dogs, lots of booze or more bolts.

Your dwarves start in military mode. You will have to clear out the any invaders to make use of the fort, and then reclaim the items and buildings in the safe sections. Once you've got a usable section of the fortress, you can start releasing your dwarves from military duty m so that they can start getting back to regular fortress life. Also note that your dwarves will want to reclaim, stockpile, sort and entomb all the bones of the previous inhabitants, so a happy fortress may require a lot of coffins, depending upon how far along the fortress was when it failed.

Reclaiming buildings

In order to reclaim a building for your dwarves to use, say a Smelter, you will need to reclaim all of the items the make up that workshop. You can do this two ways. First, you can hit [t] and move the cursor over the building, which will show all of the items within the building. This includes the materials used to build it. Just hit [f] on each one to reclaim those items. Alternatively, when you are reclaiming items via the Stock screen any items that are part of a building can be reclaimed there as well. However, you won't know which ones those are, so for specific workshops it's easiest if you claim each one separately.

Remaining living dwarves

If you abandoned your fortress before all your dwarves died, you may see some of the previous occupants wandering around. Currently, that's exactly what they'll continue to do - wander aimlessly. If they die, they will go to your graveyard stockpile, but your dwarves don't care if they're entombed or left to rot. Mostly they just get in your way, but a few of them may be useful. They will not use your workshops, but fisherdwarves will fish, endlessly flinging their catch onto the ground for others to pick up. An exception to this is any insane dwarves that were left in your fortress when you abandoned it will remain hostile to the reclaiming forces as well.

Remaining monsters

If you lost the fortress to a megabeast or a goblin siege, then the monsters will still be around, but hidden on the unit list. When a monster is discovered, it will be announced with "an ambush, drive them out". A reclaim party is unlikely to need an anvil, so trading it for an army of dogs will help to keep numbers in your favour.