I recently (half an hour ago?) installed a mod through Steam called Crimson Nirnroot Quest Locations. As the name suggests, it's supposed to add markers for the Crimson Nirnroot locations in Blackreach. After subscribing, installing the mod, and restarting the game, the mod did not seem to be working--there were no markers added (see the third note at the bottom of this post)--so I unsubscribed via Steam and then deleted the mod using the Skyrim home screen (Data Files > re-checked the mod > Delete Selected).

After deleting the mod, I noticed that several map locations seemed to be off. (I have no way of knowing if this was also an issue when the mod was active, since I only kept it running for a few minutes.) The marker for the location of the Elder Scroll kept jumping around the map (I'd go to the location indicated and enter a building at that site, and then the marker would move to a different building). Eventually the marker moved out of Blackreach entirely and showed up near the Loreius Farm. Meanwhile, the marker for my location is now showing up northeast of the Driftshade Refuge (I'm in Blackreach).

I've tried going back to a previous save point, but that doesn't fix the issue. (The quest marker appears over Alftand on the main map, and on the door to the Alftand Cathedral--though the arrow is kinda weird, with three arrows stacked on top of each other--in the local map.) I also tried reinstalling the mod, but that doesn't do it either.

What's going on here?? What did I break--and how? More importantly, how do I fix it?

Notes:
- The other mods I have downloaded are Complete Skyforge and Stones of Barenziah Quest Markers, both also through Steam.
- I'd love to try and uninstall-reinstall Skyrim to see if it would fix anything, but unfortunately I have very limited Internet data so that's not an option.
- I found this in the comments section for the mod in question on Steam, in response to a comment that the mod didn't work: "you have to drop all your crimson nirnroot from your inventory and take it back. Then the quest 'A Return To Your Roots Markers' starts. Now you only have to follow this quest and you see the markers"
- If you have any ideas, PLEASE help. This is technically my husband's game (even if it is on my computer) and I'd really like to get this issue sorted before he gets home from work in 4 hours.

hmm

Come to think of it, I can't conclusively say that it was the mod that caused the problem; it does seem likely, though, given that everything seemed all right with the map and markers until after I installed/uninstalled the mod. But I could conceivably have missed something before, or it might have just been coincidental that it started showing up right when I tried out the mod.

Try resetting your .ini file. If you don't know where that is it's: Documents -> My Games -> Skyrim -> Skyrim. Just delete that and re-establish your graphical settings. Or cut it out of the folder, then start up the game to see if that makes a difference to your issue, if it doesn't then simply paste the Skyrim file back into the Skyrim folder, overwriting the one the game had just created.

I hope this helps.

Also while this isn't necessarily an issue caused by the use of the Steam workshop for this particular title, I would still heavily recommend using and downloading your mods of the Skyrim Nexus pages instead and use Nexus Mod Manager to install and uninstall, it's fast and it's a heck of a lot more safer for the integrity of your Skyrim saves to avoid dirty mishaps caused by Steam's auto updating of installed mods.

Can you just revert to a previous save, before the mod was installed?

Southern Discomfort -- I just tried what you suggested, but unfortunately the markers didn't move back to where they should be. Thanks for your tip about Nexus vs Steam, though. I'll be sure and do that next time.

Jesuis -- I've tried that too, but to no avail. If I go back to a point when I was still in Alftand (several hours before I installed the mod), the markers are in the right place (though the one over the door to Blackreach is actually three arrows stacked on top of each other, as opposed to the single arrow that should be there), but as soon as I go down to Blackreach the marker for my position and the one for the Elder Scroll quest both jump across the map. Same thing happens if I work from a save point several days ago and head back to Blackreach.

Also: I just noticed that, on the local map, most of the locations aren't showing up. It'll show the buildings nearest to me (or in the area that I visited most recently, I'm not sure which), but none of the others--not even if I've been in that building before.

Right, apologies if I'm just being a bit of an idiot here (it is rather late for me at the moment).

Are you talking about the local map here or the world map? The reason why the map markers might be jumping across on the local map may be because the game has calculated that the faster way to these objectives (such as retrieving one of the elder scrolls) might be through another exit point in Blackreach; the area is massive and is riddled with lots of potential access points.

If I am just being an absolute muppet then another suggestion would be to simply deactivate these quests in the quest log and reactivate them again.

If I can find some way of uninstalling/reinstalling Skyrim (i.e., packing up my desktop and moving it to a place where I can get wifi), do you think that would solve the problem? Or do you think it's a problem with my particular saved file, and that I just have to start over (not something I particularly want to do, since this is my first playthrough, but if that's what it takes...)?

Eh, unfortunately they're actually jumping across the world map. Before I go into Blackreach, the marker for the Elder Scroll is over Blackreach. As soon as I'm inside, though, that marker is suddenly over by the Loreius Farm, and the marker for my position has moved beyond the Driftshade Refuge.

And, yeah, I've also tried deactivating and reactivating the quest. But, nope, that doesn't work either.

It's always worth trying to "verifying integrity of game cache" before completely reinstalling a game. To do this go you Skyrim in your Steam library, right click on Skyrim and select properties and on the "local files" tab select "verifying integrity of game cache". This will scan the local file of the game on your hard drive looking for anything that is missing from the default version and then it will redownload any missing folders.

You could try just making a quick new character to see if any map markers are displaced, this would certainly solidify the problem as either being contained to your save files or the game files itself.

Thanks for the tip; I'm trying that now. I'll post again when I get the results.

Ok, so the integrity verification is stuck at 0%. From what I've read (while waiting for it to... not do anything), this is a fairly common problem. The most common solution given is to uninstall-reinstall. But, of course, that's not an immediate or remotely convenient option for me. So I found this one:

Right Click -> Backup Local Content
Right Click -> Delete Local Files
Restore from backup

Does that sound like a good idea? (I'm running the backup now.)

Also: Might the issue that Steam is having with integrity verification have something to do with the gameplay issues I've described?

I can't say I've ever bothered to with the backup option, if I've ever had to reinstall a game I've just dive straight in with the process. You shouldn't have to worry about game saves though, they shouldn't get affected by this process since they aren't saved in the same local as the game's files.

I'm shutting down, good luck with solving your problem. If it doesn't then I hope someone with my knowledge of this may be able to provide a fix.

Thanks much for your help. I guess I'll keep on trying...

Have you tried re-installing the mod again, then seeing if the problem goes away? Do you have the same problem on a New Game?

Skyrim doesn't like it when you rip out a mod and continue on. Bits of the mods data get saved into your saves. After you remove a mod, Bad Things™ happen when the game still tries to do stuff with things that are no longer there

- Hypno

You should be able to start the game and enable or disable mods at your whim. Instead of starting it with say SKSE running the game, start it with the icon for Skyrim on your desktop. When the very first screen comes up where you click play game there is also a selection for "data files" if you click it you can check or uncheck all mods that are installed on your Skyrim installation. So when you are having trouble like you describe go to the data screen and disable mods one at a time to find out which one is causing the problems...

Map markers are considered baked in data. Once they're changed, there's no unchanging them. So if this mod has screwed them up, they're going to stay screwed up permanently. It's been my experience that not even using another script to force the changes to undo will actually work.

You're either going to have to live with the results of uninstalling that mod, or reload a save from before you began using it.

I did try that. It didn't change anything, though.

Ok, so I think that this has actually been a very stupid question on my part, mostly. Correct me if I'm wrong here, but I think this is what was happening:

Blackreach is so insanely huge that, when you're in it, you may well be almost halfway across the map from where you entered it. For whatever reason, when you're in Alftand, the marker for your position on the world map stays put right where the Alftand marker is, even though you're actually rather far from that point. However, when you move from Alftand to Blackreach, the map decides to switch over and start putting your marker where you actually are--so it ends up looking like you teleported quite a distance, when actually it was just the map finally catching up with you. The same happens on the world map with the quest marker, which sits on top of Alftand until you're in Blackreach, at which point it bounces out a ways to where it actually is.

So... if I'm right, then this isn't a glitch per say, just weird and rather misleading map display information.

That does, however, leave two slight issues unresolved:

1. When I'm in Blackreach, only the buildings closest to me display on the local map. This could just be the way that the local map works, and it only shows up in Blackreach because it's the only dungeon-type-place big enough for it to matter. (I'm guessing.)

2. Again when I'm in Blackreach, the quest marker for the Elder Scroll's location doesn't show up on the local map until I'm close enough to the building for it to display. This could be because my above guess about how the local map behaves is correct... however, from what I've read, this quest marker usually appears on the map as soon as you enter Blackreach. If that's true, then there is some little bug going on here.

By now I've managed to find my way to the Elder Scroll (I did have to use a walkthrough to get there, though, without the quest marker to guide me), and so far I haven't noticed any issues anywhere else. Feel free to continue to speculate on the other potential issues I mentioned; however, so far as I'm concerned, case closed.

In the meantime, thank you so much to everyone who answered! I appreciate it immensely, and definitely learned a few good cautionary bits of information about mod usage.

Here's a link to a modding Skyrim guide by http://www.youtube.com/watch?v=RxQ1JN_X-_Y&feature=c4-overview-vl&list=PLE7DlYarj-DdhDG41roBVJfNCqvO5MmKP. Watch these to get more comfortable to modding your game.