Tes4Mod:A General Order for Installing Mods

This is a guide to help expedite the process of figuring out the order in which to install multiple mods, especially large numbers of them. Most mods do not overlap with each other so much that there is a specific installation order for most mods; therefore, acknowledging some basic shared properties of various types of mods, most modified setup could be installed in one go (if using a utility the affords ordered installation). The goal of the organization below is to have the fewest logical groupings, while minimizing "exceptions." That makes it a good skeleton for organizing BAIN packages as well.

:Note: BAIN users, install "later" and "after" means should have higher priority, a bigger number, in the package list. Like wise, mods that should be installed "before" another mod should have lower priority, smaller numbers. The numbers on the following groups match the general priority of installation in the package list.

The Install Order
 
:Note: Most examples mentioned in this list are linked in Types of Mods.

#Original Files (backups)
#* Content: Video archive, Shaders archive, Music archive
#* Conflicts: every replacer that replaces files in the contained folders
#* This group is useful for restoring the backed up folders after using UI mods, video replacers, etc. This group can go anywhere, but having it installed first (at least in BAIN) may make more sense, as these files are truly installed first (when you install Oblivion from the disc or Steam). Therefore, in BAIN, the package will be green if none of these files have been replaced, and yellow if some files have been overwritten. It makes for a good sanity check. 
#*:Note: Remember that the original Meshes, Textures, Sounds and Trees are packed in BSAs, so there should not be a reason to install package containing these original files loose. If you are not seeing the original files, check your BSA Redirection settings in BAIN or OBMM and make sure nothing has been installed overwriting them. (See BSAs and Archive Invalidation for more information about BSAs, and see PyFFI if you have you have not packed or do not know how to pack your loose PyFFI-optimized meshes back into a BSA.)
#Utilities
#* Contents: plugins, few data files, INIs
#* Conflicts: few to none, not serious
#* These mods rarely have conflicts with other mods. One notable exception is FormID Finder, conflicts with the UOP because they both contain missing mesh marker meshes. If you really want that mesh so badly, install this mod after the UOP (which means giving it a number higher than the UOP in BAIN.)
#* Examples: FormID Finder, Kuertee's Actor Details, Streamline
#Game Tweaks (Immersion & Special Items)
#* Contents: plugins, few data files (typically custom files), INIs
#* Conflicts: rare, not serious
#* Game Tweaks (and related mods) have few or no data file conflicts. They may contain data files, but they are usually new files. There are some notable exceptions because some game tweaks that truly are not UI mods do include menus to extend certain functionality (i.e., Enchantments Restored over Time, LAME.)
#* Examples: Deadlier Sneaking, Common Oblivion, Harvest Flora
#New Buildings & Locations
#* Contents: lots of different data files (mostly custom) and plugins
#* Conflicts: few to none, not serious
#* They can contain just about every type of data file, but they usually add only new contents, so there is nothing major to worry about here.
#* Examples: Bank of Cyrodiil, Bartholm, Glenvar Castle, Vaults of Cyrodiil
# Official Add-ons (DLCs) & Unofficial Official Patches
#* Contents: plugins, data files (replacers), BSAs
#* Conflicts: many, supposed to conflict
#* This category, putting the DLCs aside, contains fixes for the vanilla game. Mods that have higher priority and overwrite these are typically fixed, so both the higher and lower conflicts are expected and safe. There are no real conflicts in this position.
#* Examples: DLCs 1-9, UOP, USIP, UOMPs, UOMPs MOBs, USIP MOBS
# Quests
#* Contents: plugins, all kinds of data files (often packed in BSAs)
#* Conflicts: cosmetic mods, some other, minor (with an exception)
#* These mods can touch about every aspect of the game. Sometimes they have incorporated other item mods, and often contain files from cosmetic mods. There is no reason that they need to win their conflicts. Most of the important files are custom. The notable exception here is that some (or one) quest mods contain music and video replacers, unlike most of the data folder, the Music and Video folders are not in a BSA, so they are vulnerable to permanent alteration; hence, the initial recommendation to backup the loose original folders.
#* Examples: Blood & Mud, Choices & Consequences, Gates to Aesgaard 1 and 2, The Lost Spires, The Mysteries of the Dulan Cult, Ruin Tail's Tale, Ungarion Memoirs: The Welkynd Sword
#Companions & NPCs
#* Contents: plugins, cosmetic files, few other types of data files that conflict (usually custom)
#* Conflicts: cosmetic mods or none, not serious
#* The NPCs mods rarely contain overlapping data files; however, companions often include files from existing cosmetic mods (i.e., Ren's hairs) instead of having plugins that depend on the user installing the cosmetic mod itself. There is rarely a reason to have the companion mod overwrite the data files from the original cosmetic mod. Otherwise, there are no file conflicts with this group.
#* Examples: Viconia, Vilja
#Big Mesh Replacers
#* Contents: meshes, textures
#* Conflicts: many, minor
#* This category in many setups will only include QTP3. It is a huge texture replacer that uses textures which require parallax meshes. The reason why it should be installed early is because the main mods that overwrite it are the unofficial official patches and aesthetic mods that contain support for it (and also require that the meshes be replaced) or individual replacers, which you want to see in the game instead of just Qarl's textures. Incorrect meshes can actually cause serious problems, so it is important that QTP3 is overridden by certain mods (i.e., the higher priority mods it conflicts with in this list, UOP, BC and AWLS.)
#* Examples: QTP3, QTP3 Redimized, QTP3 Redimized Reduced, QTP3 further Reduced
# Overhauls & Creature-Adding Mods
#* Contents: plugins, all kinds of data files (some packed in BSAs)
#* Conflicts: many, serious (pay attention to the ReadMes and the instructions found on this site)
#* This is probably the only section where alphabetical ordering is practically a worthless effort (though you could alphabetize the patches for an individual overhaul.) There is specific installation order depending on which overhauls you are using. The conflicts that originate outside of this group are found with overhauls and creature-adding mods in this section. This site has the recommended installation order for most of them. (FCOM's recommended installation order applies to most overhaul configurations, even ignoring the overhaul not used in your setup.)
#* Examples: Cyrodiil Upgrade Overhaul, FCOM, Francesco's Leveled Creatures Items mod, Martigen's Monster Mod, Oblivion War Cry, Oscuro's Oblivion Overhaul, Tamriel Immersion Experience
#New Items (Armor & Weapons)
#* Contents: lots of different data files (primarily meshes and textures) and plugins
#* Conflicts: varies, new item compilations, overhauls, quests, not serious
#* If you run an overhaul, it probably includes a number of new items mods, so there are bound to be data conflicts. The reason to load them after the overhauls is because the stand-alone mod may contain newer files. If that is not the case, then simply do not install the stand-alone mod. However, it is perfectly reasonable to install these mods when some or all of their data files are overwritten by compilation-type mods because the original plugins may still add the items with an availability and variety not offered in the overhaul.
#* Examples: Bob's Armory, Loth's Blunt Weapons, KD's Circlets, Pure Steel Blade, Slof's Oblivion Goth Shop I, Slof's Oblivion Robe Trader, Xiamara's New Amulets
# City & World Aesthetics
#* Contents: plugins, all kinds of data files (some packed in BSAs)
#* Conflicts: other mods of this type, big mesh replacers, minor (have support)
#* The mods that have lots of overlap with other popular mods (i.e., QTP3) offer support for it. This group probably has more support modules for other mods than any other group (i.e., Unique Landscapes patches.) This is a great position in your installation order for them because these mods need to win the mesh conflicts, not texture contests. The biggest of these, AWLS and Better Cities, do not conflict with anytexture replacers. Just make sure to download support options when they are available. For those of you using shader replacers and mods that contain shader changes (i.e., some OBSE mods) absolutely must back up the Shaders folder. In fact, everyone should back up that folder. For some reason, they can be warped during installation or in other cases where the user did not deliberately modify them. (There is a link on this site to replacement 1.2.0416 shaders in the event of a mishap.) Bad shaders cause bad problems. (Screen effects users should get the updated version of the OBGE DLL produced by the OGE team.) OBMM is theONLY utility that fully supports shader installation. Even if that is the only mod you use OBMM for, install it. (Although there are many other reasons to have OBMM installed anyway.)
#* Examples: All Natural, Animated Window Lighting System, Better Cities, Enhanced Weather, Let There Be Darkness, Natural Environments, Unique Landscapes
# User Interface (UI)
#* Contents: fonts, Menus files, Music (has no specific place to be), Textures, Videos
#* Conflicts: other UI mods, other mods that touch menus, serious!!!
#* The mods mainly conflict with one another and certain game tweaks. You musthave support for these conflicts or something will be broken, and the chance that they cause a serious problem with the game is not small. You must also be aware that there are UI mods that do not replace the HUD and main menus (i.e., Keychain, HotKey mods, etc) and their conflicts can be just as serious. This section also contains the menu video replacers. Users of such mods must remember to back up the Video folder. (Many of the serious things to watch out for will be noted in the next section.)
#* Examples: Dark UI, DarN UI, DarkUIdDarN, Immersive Interface, Keychain, Menu Video Replacer Scenery, Toggleable Quantity Prompt, Super Hotkeys
# UI-Modifying Game Tweaks
#* Contents: plugins, menu files, INIs
#* Conflicts: UI mods
#* These mods almost always conflict with UI mods, but UI mods either include support for these mods or vice versa. Since the leveling mods people use are usually more current, there is a better chance that the leveling mod contains the right compatibility support for the popular UI mods.
#* Examples: Kobu's Character Advancement System, Less Annoying Magic Experience, nGCD, Oblivion XP, Progress, Realistic Leveling, Supreme Magicka
# Texture Replacers
#* Content: textures (some also contain new meshes or plugins)
#* Conflicts: other texture replacers, minor (users choice which "wins")
#* The installation order of these mods is very important, especially if you plan to install texture replacers that overlap with each other. For example, you want to use Bomret's Normals to cover what Corepc's Vibrant Textures do not. In that case, you should install Bomret's mod first, of course. However, many users use more than ten texture replacers, and sometimes three or more of them may touch certain files, but the user desire one version over the other. Plan this group out first. Beyond special details in ReadMes there is no set order for these. Install them in the order that is most aesthetically pleasing. BAIN users can easily switch the order of the packages in the Installers tab on a whim and fix the change by using the anneal function, but the other installation methods are not as flexible. Making mistakes with the multiple texture mods even a tenth of the size of QTP3 become very frustrating, not to mention, non-BAIN users have no sure way of knowing which version of a file is installed once they start uninstalling mods with overlapping files. The ONLY way to cleanly uninstall mods with overlapping files with the other installation methods is to uninstall every mod that shares that file, or reinstall one of those overlapping mods. 
#*:Note: Detailed Terrain contains shaders. Only use OBMM to install at least that part of the mod. BAIN users should add "--" to the beginning of the Shaders folder in the packages so that BAIN ignores it.
#* Examples: Ampolex's Texture Pack, Better Night Sky, Detailed Terrain, FineWeapons, RustyItems, Magic Shields, Real Lava, Real Night Sky, Vanilla Hair Replacer
# Other Replacers
#* Content: plugins (maybe a mesh or two?)
#* Conflicts: none
#* These mods do not belong in the other groups. Most of these will be graphical shader replacers. They do not actually edit shaders; rather, they modify certain visual effects by tweaking certain plugin records. This section is mainly here for sake of organization, but maybe they can be thrown in with the other "magic" mods because those mods typically contain these types of changes (usually in optional modules.)
#* Examples: Initial Glow, Visually Enchanted Customized Fixed
#Animation Mods
#* Contents: plugins, KFs (animation or idle pose files, typically found in the "Meshes\_Male")
#* Conflicts: other animation files, minor, quest/companion mods that add custom animations to NPCs
#* Whether talking about data files or plugin records, animation mods usually conflict with other animation mods if there are conflicts. There are many animation mods that add new KFs or replace original KFs (i.e., Seph's H-to-H replacer.) If two animation conflicts replace the same animations, you should know by reading their descriptions. Just make sure the one you want is installed later.
#* Examples: Actors in Emotion, Seph's Hand-to-Hand Animation Replacer
#Cosmetic Mods & Body Replacers
#* Content: plugins, cosmetic files (meshes and textures)
#* Conflicts: other cosmetic mods, these should override other mods, not serious
#* Generally, if cosmetic mods contain multiple versions of the same files, let the newer one load later, just in case its files are updated in some way. If, for some reason, a cosmetic compilation replaces textures for vanilla races, make sure it either has support for your body replacers or have the body replacers load later. Also, without a Bashed Patch, only one cosmetic mod that overhauls the Vanilla races can be installed at once. For example, Race Balancing Project and Ren's Beauty Pack Hairs Only do not work together on their own; however, with a Bashed Patch the hairs from the Hairs Only version can be imported, while the main plugin, which conflicts with RBP, can remain deactivated. If both mods are more "full" cosmetic compilation packs, meaning they do more than add hairs or eyes to the Vanilla races (i.e., RBP and BP) even a Bashed Patch make them compatible because they contain new records that cannot be imported (i.e., new races.) Keep an eye out for the eye meshes issue as well. A race can only have one eye mesh. Therefore, if Elaborate Eyes (EE) or BP (which contains EE) is installed, quest mods and race mods that add new eyes using the Vanilla eyes mesh (which is the case with most mods of those types, including Ren's) are incompatible with the current setup. They cannot be used together. If you really want to use the other mods, either install a patch, use a version with converted eyes, or look for a different compilation pack. Lastly, many of these types of mods have multiple versions of the main plugin. Only install ONE.
#* Examples: Beautiful People (BP), Race Balancing Project (RBP), Ren's Beauty Pack, Robert's Male Body, Robert's Female Body, Robert's Female, Robert's Female for Mod, Robert OOO Armor, Robert MMM Armor
#Character Texture Replacers
#* Content: textures
#* Conflicts: cosmetic mods, body replacers, other character texture replacers (users choice)
#* The organization of this section is all up to the user. This section should load last because there is no point in installing a unique facial texture just to have it overwritten. Make sure the body textures support your body, or the textures will not match and appear deformed in-game. Again, these are texture replacers, so there is no required installation order within this group. Choose the order most to your liking.
#* Examples: Enayla's Dremora Face Texture, Enayla's Facial Textures, Enayla's New Face Textures, Improved Facial Textures, Kendo's Orc Textures
#Your Projects
#* Content: cleaned plugins, (dummy plugin for loading BSAs in the absence of DLCShiveringIsles.esp), tweaked (cleaned) plugins, patches, merges (could also contain data files)
#* Conflicts: things that are patched
#* Patches have to overwrite the mods they patch, and this is the best position from which to do that, last. 
#*:Note: Users of the Cyrodiil Terrain Map should have a patched archive of some kind to contain the fixed world map textures. See PCS Library for the fix. 

See Also
BAIN Installation
Manual Mod Installation
OMOD Installation