Go to Vault 34, unlock the armory door from the Overseer's office and pick the Very Hard locked footlocker to retrieve the pulse gun. A key to the footlocker can also be found in Pearl's barracks at Nellis AFB.
Return to Elder McNamara and show him the advanced technology.
Defuse the situation with the Brotherhood paladins outside the bunker.
If Veronica decides to leave the Brotherhood, they allow her to leave and tell her to never come back.
If Veronica decides to stay with the Brotherhood, the paladins must be convinced she is not a liability with a Speech of 95, scared off momentarily with Terrifying Presence or killed.
During the search for the Euclid's C-Finder, Sarah Weintraub in Vault 21 tells the player that a man with a "strange metal collar" already purchased it. Veronica may comment "I don't like the sound of this. Hope that collar isn't what I think it is. What did you do, Elijah?" upon hearing this. When the player finds the man in Freeside, he is already dead, with his head blown off. Veronica doesn't comment any further about the body.
Veronica's final conversation with the Elder is based on which technology item is currently in the player's inventory when they step into the Elder's office, not which technology the player selected to pursue in dialogue with Veronica.
Sometimes Veronica might refuse to accept any triggers required to start the quest, due to the game forgetting to give her scripts required for her to respond to them.
PCPlayStation 3Xbox 360 If the player has completed There Stands the Grass prior to starting this quest, it's impossible to finish the quest with the "farming technology" even if the data was not destroyed by Keely. The quest directs you to the terminal in Vault 22, which no longer has the data.
PCPlayStation 3Xbox 360 Activating the Archimedes II weapon system and gaining the Rangefinder before you initiate this quest will automatically flag the journal to tell you to return to the Elder after activating the terminal in Gibson's shack. If you go get a second technology, the quest is seemingly broken. Neither Veronica or the Elder will have conversation options to continue further, and neither will initiate their dialogue scripts between the two, despite there being periods where you cannot talk to either one after coming close to the Elder.
PCPlayStation 3Xbox 360 After the Brotherhood Paladins confront you outside the bunker Veronica may become immobile.
PCPlayStation 3Xbox 360 After taking the Rangefinder option, if you use HELIOS One to power the grid instead, you should be able to discuss the other two options with Veronica. However, only her normal dialogue appears when talking to her, rendering the mission unsolvable.
PlayStation 3Xbox 360 In some cases, usually after a long playtime or getting to a certain point in the game, Veronica will not enter any of the dialogue triggers.
PC When the Paladins initially deliver their ultimatum, sometimes only one will become hostile and three will run away, still friendly. The quest completes normally after killing the one hostile, but upon returning to the bunker the three have come back, deliver their ultimatum again, and attack. After this fight, Veronica refuses to follow you, and will sometimes start an unprovoked dialogue with you but only give the standard "what's up?". This appears to be caused by her attempting to deliver the quest-ending dialogue but, already having delivered it, getting stuck and refusing to budge until it's delivered.
PlayStation 3 The encounter with the Paladins outside the bunker may not spawn, stopping the quest from progressing. This can be fixed by re-entering and exiting the bunker until they turn up. It may take four or five attempts before they appear.
Xbox 360 Whilst trying to complete the "Go with Veronica to talk to the Brotherhood of Steel elder at Hidden Valley" section of the quest, Veronica enters the Hidden Valley Bunker and instantly runs to the intercom. She then proceeds to do nothing other than say "See you around" on a continual loop and refuses to engage in conversation. Upon fast traveling to Gibson's shack, Veronica just walks off to the intercom at Hidden Valley and does the same thing.
Xbox 360 After obtaining the pulse gun, your Pip-Boy may still show the objective "Find the pulse gun in Vault 34".
Xbox 360 After completing the quest Veronica may stop following you. Fast travel and dismissing and rehiring her has no effect. Reloading to a previous save after entering Vault 34 causes a "DLC not installed" error message and forces a restart.
Xbox 360 If done after helping Paladin Hardin in the Still in the Dark quest, but before Elder McNamara is ousted, Hardin and McNamara will not talk to the player, and the Brotherhood quests will be locked. However, this does not have any affect on Veronica's quest itself. This can also cause Veronica to stop following you.
Xbox 360 It is possible for the keys and information on the pulse gun at Nellis Air Force Base not to spawn in the cabinets rendering the "easy way" through this part of the quest way to be impossible.
PCPlayStation 3Xbox 360 Quest stage 30 directs the courier to a pawn shop in Freeside. But the pawn shop to visit is Miguel's Pawn Shop in Westside. However the map marker points to the correct location. Also the visit can be skipped without consequences because Miguel doesn't have any useful information.
PC The trigger problem can be fixed by targeting her in the console and entering addscriptpackage 0014779f. Please note this is not permanent, and has to be done every time a player wants to activate a trigger.
Solution to the dialogue between Veronica and the Elder freezing or not starting at all during the first phase I Could Make You Care: upon arrival, stand beside the Elder's table and raise and lower (twice if necessary) your Pip-boy any time the conversation freezes. You might lose some sentences, but the first step of the given quest (Bring Veronica to the Elder) will be completed, and Veronica gives you the next step of the quest (the terminal thing) as soon as you leave the Elder's room.
PC You can also use the console: "e32a9".sayto e2f87 VMS49ElderDiscussion1 or "e2f87".sayto e32a9 VMS49ElderDiscussion1. Replace the 1 at the end with a 2 if you're delivering the technology.
Solution to Veronica not following after I Could Make You Care: During the battle with the paladins, KO Veronica before you kill the last paladin. When she wakes up, you can manually talk to her twice for her standard dialog (this won't work on hardcore mode for obvious reasons).
If she becomes immobile after completing the quest, try talking to her using the companion wheel. She will thank you for helping her out and she should start following again. If this doesn't work try one of the other fixes below. There is also a fix on NewVegasNexus: http://www.newvegasnexus.com/downloads/file.php?id=35943
If Veronica won't follow you anymore (she simply stands in place and won't move, despite being able to interact with her) after you fight the Paladins outside the Hidden Valley Bunker (After suggesting she stay with the Brotherhood to gain her Bonds of Steel Perk), simply travel to Gibson's Shack, re-download the data from the computer, talk to her so she brings up the conversation about what technology to pursue, choose the technology you choose initially to complete the quest, exit the conversation, talk to her again, enter her workbench and craft ANY item (1 ammunition conversion works just fine), after the item is crafted and added to your inventory she should now follow you again. Test by simply entering into sneak mode, if she crouches with you she is now following you again. Solution works for Xbox 360, PS3 and PC.
If Veronica won't follow you anymore, you'll have to go back to before the part of the mission where she speaks to the elder after you retrieved the notes, and directly tell her you want her to leave (don't suggest for her to stay, and don't allow her to choose for herself).
If Veronica gets stuck and won't follow you anymore, and then you get the infinite loop once you get to the comm terminal at Gibson's Shack, you'll have to restart the mission (from a previous save) and work back to the part where she speaks to the elder after you retrieved the notes, and directly tell her you want her to leave (don't suggest for her to stay, and don't allow her to choose for herself). Then go to Gibson's Shack and access the comm terminal, and once you do, it will say (in the upper left side of your screen) "COMPLETED: Access Father Elijah's notes for the comm terminal", and upon exiting the terminal, Veronica will automatically start talking. After you choose one, it will give you the option to exit the dialogue, and Veronica says, "I like the way you think...".
If Veronica missed too many triggers to initiate her companion quest, the console command set "145f85".ngreetingpending to 1 will advance her companion quest dialog conversations. This may need to be done up to 3 times, allow a few seconds after the console command for her to initiate dialog. Since there are always three triggers available (McCarran, Vault 3, Nelson/Cottonwood Cove), it's generally going to be better to trigger the quest "normally" - use the console only if the regular triggers won't work.
If you have already completed There Stands the Grass and you are unable to download the Vault 22 data: it's possible to reset the mainframe terminal by using the console command set e6a6a.DataState to 0; you can then re-download the data to complete the objective. This should even work if the data was deleted. (Or you can talk to Veronica about the technologies and switch to a different objective.)
If the dialogue options do not open automatically give Veronica some Formal Wear for the unmarked quest You Make Me Feel Like a Woman and she will most likely not respond. However, sit down, and when you stand back up, open the companion wheel, go to the talk to option, and then talk to her about trading equipment, take the dress back and put it back in, and when you leave the triggers should work.
If Gibson's Shack freezes upon trying to enter, ask Veronica to wait outside. You can download the data without her, and her dialog will automatically trigger when you exit and see her again.
Sometimes there will be a non hostile paladin frozen outside the followers outpost when you return, you will not loose any karma for killing the paladin.