With the exception of Fighter's Stronghold, all the add-ons can be purchased in a bundle on the Knights of the Nine PC retail disc. The add-onss can no longer be purchased separately online, but were originally available from Bethesda's Online Store and . All of the add-ons are included in , which is now the only way to legitimately purchase Fighter's Stronghold for PC. The Game of the Year retail disc (for any platform) includes only Knights of the Nine and the Shivering Isles expansion, and none of the other eight add-ons. Add-ons bought from Bethesda's Online Store are not compatible with versions of Oblivion from Steam.
Xbox 360 players can obtain all of the add-ons from the with an Xbox Live account and a high-speed Internet connection; only Knights of the Nine and Shivering Isles are included with the Game of the Year retail disc. Both the Thieves Den and Wizard's Tower add-ons were also provided on the Official Xbox Magazine's 67th promotional disc.
For Playstation 3 players, Knights of the Nine is included on all versions of the game and Shivering Isles is available as a download or as part of the GOTY edition. The other add-ons are not available to PS3 players via download or retail disc.
|Fighter's Stronghold||$1.89||150||1.1.511||Battlehorn Castle: Rescue Battlehorn Castle from marauders, and claim it as your own.
|Horse Armor Pack||$1.99||200||None||Horse Armor Pack: Protect your horse from danger with this beautiful handcrafted armor.|
|Knights of the Nine||$9.99||400||1.1.511||Knights of the Nine: A fallen King has been unchained from the darkness of Oblivion to seek vengeance upon the Gods who banished him. Only a champion pure of heart can vanquish the evil that has been released upon the land. You must heed the call, reclaim the lost relics of the Divine Crusader, and return the Nine to glory. New dungeons, characters, quests, and mysteries await.
|Mehrunes' Razor||$2.99||250||1.1.511||Unearthing Mehrunes Razor: Conquer one of the deepest and most challenging dungeons in all of Cyrodiil to claim this fearsome weapon.|
|Orrery||$1.89||150||None||Repairing the Orrery: Harness the power of the stars. Rebuild the defiled Orrery and unlock the secrets of this Mages Guild Inner Sanctum.|
|Spell Tomes||$0.99||80||1.1.511||Spell Tomes: Add "Spell Tomes" to the world's random treasure which grant you new and powerful magic spells, just by reading them.|
|Thieves Den||$1.89||150||None||Dunbarrow Cove: Uncover a famous pirate's lost ship and claim it for your own.|
|Vile Lair||$1.89||150||1.1.511||Deepscorn Hollow: Deepscorn Hollow is an asylum for the wicked, a refuge from the persecution of the virtuous.|
|Wizard's Tower||$1.89||150||None||Frostcrag Spire: In the frozen mountains of Cyrodiil stands Frostcrag Spire, a tower of wonders for your magic-oriented character to call home.|
- Shivering Isles: Many mysteries await your investigations in the twisted reality that Sheogorath calls "The Shivering Isles".
- Details on how to obtain Shivering Isles are provided on the Shivering Isles FAQs page.
Some people have reported problems installing the PC versions of the add-ons. Note that most of the add-ons require that the v 1.1 patch be installed. The following causes seem to be the most common:
- Download problems
- Problem: Page errors or truncated files (files that are too short when downloaded), especially on the day that a new add-on is released.
- Cause: The download servers can get overloaded, causing downloads to be slow.
- Solution: If the downloaded file is shorter than it should be, or if you get strange error messages during installation, try the download again. You don't have to pay again.
- Problems with activating
- Problem: Unable to activate the product using your serial number.
- Cause 1: The authentication servers can also get overloaded.
- Solution 1: Try again in just a few minutes.
- Cause 2: Your firewall could be blocking the authentication.
- Solution 2: Turn off the firewall.
- Hangs after activating
- Problem: After activating, the install screen does not appear and the add-on installer hangs. Killing the installer and/or re-booting, then re-launching the installer simply hangs without attempting to activate.
- Cause: Conflict with CTFMON.EXE.
- Solution: Do a clean boot (directions are on the Microsoft site). Advanced users can use the Task Manager to kill CTFMON.EXE (but beware, it may re-launch).
- Hung install
- Problem: The progress bar pauses and nothing appears to happen when installing the file.
- Cause: The add-ons' installation programs are very sensitive to system settings and will often fail.
- Solutions: (Try these in order.)
- If your account doesn't have administrator options, log in as an administrator and try again.
- Turn off virus scanning software.
- Reboot into safe mode with networking and attempt to install.
- Try a clean boot
- Windows XP directions at Microsoft site
- This has the highest chance of success.
- Caution: If you have a non-Microsoft firewall, you may sometimes be unable to connect to the Internet when performing this clean boot. To avoid this problem just be sure not to deactivate the firewall on step 3 under "Manual Steps to Perform a Clean Boot in Windows XP" on the link above.
- Xbox Live Connection
- Should your connection cease during any download of any add-on, you don't need to worry. Reconnecting and resuming your download from where you left off will not hamper your gameplay, save, cache, or files. Your progress bar may be pushed back a bit though.
- Secure Loader or Aladdin HASP error
(Note: This primarily affects 64-Bit Windows XP and Windows Vista, but has also been seen on 32-bit editions of Windows XP.)
- Problem: You receive one of the following two error messages with error code 0x80040702:
- The Aladdin HASP SL Runtime protecting module "<folder name>\bethsec.dll" could not initialize properly because it is incompatible with the current platform version. Please contact your product vendor.
- The Secure Loader used to protect this software has encountered a fatal error. Please contact your software vendor.
- Cause: The Secure Loader is incompatible with 64-bit Windows XP and Windows Vista; this seems to relate to a known problem with the InstallShield software and msvcrt.dll.
- Solution 1: Install them on another machine or partition with an earlier operating system and manually copy the files in the data directory to your main machine. (Virtual Machines are also a good choice here, since you don't actually need to play the game, just install the files.)
- Solution 2: Buy the box set for Knights of the Nine. The installers in that boxed set are compatible with Windows Vista. According to Bethesda support, there is no other work-around (see talk page for details), however the solutions below may work. Important: If you cannot get any of these solutions to work, and you've already downloaded the files, don't delete your downloads. A future patch may allow their installation on Windows Vista.
- Solution 3: (Tested only on Windows Vista 64-bit.)
- Buy and download the "Knights of the Nine Downloadable Content Collection" package from http://direct2drive.com/. This package works with both the retail and Direct2Drive versions of Oblivion. It contains all of the official add-ons except for Fighter's Stronghold. The Shivering Isles expansion sold by Direct2Drive is also confirmed to work on Vista 64-bit.
- Solution 4: (Tested only on Windows XP 32-bit.)
- Reboot and hit F8 immediately as Windows boots up. When prompted with a menu, select "Safe Mode with Networking" (required for Internet activation; for phone activation, regular "Safe Mode" will do). Re-try your install. (Note: this may be a bit challenging, as there is limited screen real-estate in Safe Mode.)
- Solution 5: (Works in all configurations.)
- (Note: With this method, you do not need to actually run the installation program. Doing so will only cause the same error messages as mentioned above.)
- Download and install Universal Extractor 1.5 or later.
- Open each add-on's executable file with Universal Extractor and extract the files using the "isxunpack method". This will place several files in a Disk1 folder under whatever folder you specify (the same folder as the executable, by default, so Oblivion_Horse_Armor_Pack.exe would create an Oblivion_Horse_Armor_Pack\Disk1 folder structure).
- Use Universal Extractor again, and in each of the previous Disk1 folders, open data1.cab. (Do not open data1.hdr.) This will create a Data1 folder in the specified folder.
- Copy the Data folder in each of the above Data1 folders to your Oblivion folder. When asked if you want to merge the two Data folders, say "Yes". (Alternatively, you can copy all the files in each Data folder to the Oblivion\Data folder, which will avoid the merge questions each time.)
- Should you wish to avoid this entire process in the future, you can use either OBMM or Wrye Bash's mod manager at this point to create mod files simply by including the entire contents of each Data folder.
- Delete all the interim files you created in the above steps.
- Launch the game, go into the Data Files section, and select the appropriate checkboxes.
- AVG Anti-Virus
- Problem: AVG Anti-Virus detects the .exe file as a trojan during installation.
- Cause: AVG Anti-Virus is detecting a false positive in the .exe file (there is no trojan).
- Solution: De-activate AVG, install the add-on(s), re-activate AVG.
(Another way involves the use of the "Resident Shield". Simply add the .exe file to the "exceptions" list, and open the file.)[verification needed — see ]
Viewing/Editing Newer Official Add-ons: Newer official add-ons (any add-on that requires installation of the 1.1.511 patch) should only be viewed/edited with the new (1.2) version of the Construction Set. Alternatively, it is possible (although not recommended) to view a newer add-on in the original construction set if you hex edit the add-on's .esp file: make a backup of the .esp file, open it in a hex editor, and change the second line from "0C 00 00 00 80 3F" to "0C 00 CD CC 4C 3F".
In-Game Formid: The pages on individual add-ons often contain Object IDs for items or spells. In all cases, the first two digits of the Object ID are listed as "xx" because the first two digits are variable, depending upon the number of add-ons you have installed and the order in which they were loaded. If the add-on in question is the first (or only) add-on you are loading, the first two digits will be "01", for the second add-on "02", etc. For more info in determining these two numbers for your setup see Formid.
- DLC Page at official Elder Scrolls website