Which achievements can be permanently lost in Skyrim?

My goal is to get all the Skyrim achievements with a single character. I got many of them already by simply playing along and completing certain quest lines.

I discovered today that it is possible to take some perfectly normal actions that will stop you from completing an achievement. In my case it is missing a daedric artifact that cannot be recovered (although there might be a workaround as long as only one is lost - see answers in the linked question).

Now I want to know if there are other "fragile" achievements like that. I am not talking about blindly killing important NPCs or other obvious stupid actions. I am interested in quest items that are easily missed or decisions you can make that will mess up an achievement. I read about all the possible troubles with Oblivion Walker, please focus on the other achievements instead. Where can I easily go wrong so that I have to play the game again from the start with a new character or load an old savegame before my blunder?

Solution 1:

Apart the now well-known Oblivion Walker as already stated here and there, it seems there are also a few others, if we listen to PS3 Trophies, that are potentially missable.

• One with the Shadows
  It seems that due to some bugs, you may miss it, particularly if you sell the Thieves Guild armor before completing the Thieves quest line.

• War Hero

  Since both of these forts can be given away during the main questline, either complete Civil War beforehand or give both forts to the faction that you side with. If you complete the Civil War questline before the main questline is finished, you shouldn't have any problems. Whether you can get this trophy or not depends on your choices. Just make sure that both forts either end up with different factions or the faction that you are no aligned with.

They may be fixed in future patches but you should be careful with current version.

Solution 2:

The achievement that you are referring to is the "Oblivion Walker" achievement, and it is the only one that can be missed. All the other achievements should be unlockable on a single playthrough, even if you make a mistake somewhere.