I'm having a similar issue. I've noticed that some map markers seem to randomly disappear. I thought that I might have been imagining it at first, but I'm certain about the most recent case. I distinctly remember having found Nocturnal's Shrine earlier and then using its map marker to fast travel to the area east of Leyawiin some time after that. When I decided to start Nocturnal's quest a while later, I was surprised to see that the map marker had disappeared. I tried going there again without using fast travel to see if I could just add it to my map again, but when I got there, the map marker didn't even show up on the HUD compass. I opened the console and saw that there were several error messages: Invalid array access - the array was not initialized. File: Map Marker Overhaul.esp Offset: 0x00000B3A Command: Let (0x1765) Error in script 1f000ed3 Operator | Failed to evaluate to a valid result. File: Map Marker Overhaul.esp Offset: 0x00000B3A Command: Let (0x1765) Error in script 1f000ed3 Invalid array access - the array was not initialized. File: Map Marker Overhaul.esp Offset: 0x00000005 Command: eval (0x1769) Error in script 1f000ed3 Operator | Failed to evaluate to a valid result. File: Map Marker Overhaul.esp Offset: 0x00000005 Command: eval (0x1769) Error in script 1f000ed3 An expression failed to evaluate to a valid result. File: Map Marker Overhaul.esp Offset: 0x00000011 Command: <unknown> (0x4200) I'm guessing there may have been more messages listed before these but they may have been cut off. I tried deactivating Map Marker Overhaul, but when I loaded the game, all of the map markers were gone! Even all of the ones for the cities that are there when starting a new game were gone. I tried renaming the Oblivion.ini file in My Documents, but that didn't seem to have any effect. I tried deactivating all of the mods to see if it would show up in Vanilla, but I got some strange results. When starting Oblivion, it would always freeze with an image of the loading screen if I press Esc to skip the intro (Bethesda logo, 2K logo, etc.). If I waited for the menu to fully load, I could select a save game to load, but then it would immediately freeze after confirming the selection. I reactivated all of the mods that I was using earlier and was back to where I started (able to run the game but with missing map markers). I tried only disabling some of the mods that I knew used OBSE v0018, making a save game, and then activating the mods again (read this suggestion somewhere on another forum). This got rid of the error messages, but the map markers are still missing. Here is the list of active mods from the Wrye Bash bashed patch output (after running BOSS and manually moving a few mods in OBMM): Active Mods • 00 Oblivion.esm • 01 All Natural Base.esm [Version 0.9.6] • 02 HorseCombatMaster.esm • 03 HrmnsOblivionScriptOptimizationv1.0.esp • 04 Unofficial Oblivion Patch.esp [Version 3.2.0] • 05 UOP Vampire Aging & Face Fix.esp [Version 1.0.0] • 06 Oblivion Citadel Door Fix.esp • 07 DLCShiveringIsles.esp • 08 Unofficial Shivering Isles Patch.esp [Version 1.4.0] • 09 LoadingScreens.esp • 0A All Natural - Real Lights.esp [Version 0.9.6] • 0B All Natural.esp [Version 0.9.6] • 0C All Natural - EW + NW + AWS.esp [Version 0.9.6] • 0D Enhanced Water v2.0 HD.esp • 0E Symphony of Violence.esp • 0F AmbientTownSounds.esp • 10 MIS New Sounds Optional Part.esp • 11 WindowLightingSystem.esp • 12 AliveWaters.esp • 13 AliveWaters - Koi Addon.esp • 14 AliveWaters - Slaughterfish Addon.esp • 15 bgShaderStandAloneEV.esp [Version 1.0EV] • 16 DLTIC-1-6.esp [Version 1.6] • 17 ChaseCameraMod.esp • 18 P1DmenuEscape.esp • 19 RD-TimeKeeper-v1-3-5minUpdate.esp • 1A Skillbookssave.esp • 1B TryBeforeYouBuy.esp • 1C Harvest[Containers].esp • 1D Harvest[Containers] - Player Home Add-on.esp • 1E Harvest[Containers] - Flat-Top Barrels Add-on.esp • 1F Map Marker Overhaul.esp [Version 2.3] • 20 Map Marker Overhaul - SI additions.esp [Version 1.0] • 21 HouseMapMarkers.esp • 22 DLCHorseArmor.esp • 23 DLCHorseArmor - Unofficial Patch.esp [Version 1.0.5] • 24 DLCOrrery.esp • 25 DLCOrrery - Unofficial Patch.esp [Version 1.0.3] • 26 DLCVileLair.esp • 27 DLCVileLair - Unofficial Patch.esp [Version 1.0.5] • 28 DLCMehrunesRazor.esp • 29 DLCMehrunesRazor - Unofficial Patch.esp [Version 1.0.4] • 2A DLCSpellTomes.esp • 2B DLCSpellTomes - Unofficial Patch.esp [Version 1.0.1] • 2C Rope Ladders v1.esp • 2D DLCThievesDen.esp • 2E DLCThievesDen - Unofficial Patch.esp [Version 1.0.5] • 2F DLCThievesDen - Unofficial Patch - SSSB.esp [Version 1.0.4] • 30 FarmAnimalsofCyrodiil.esp [Version 1.4] • 31 TIE.esp • 32 allinonebasement.esp • 33 DLCBattlehornCastle.esp • 34 DLCBattlehornCastle - Unofficial Patch.esp [Version 1.0.4] • 35 DLCFrostcrag.esp • 36 DLCFrostcrag - Unofficial Patch.esp [Version 1.0.4] • 37 Knights.esp • 38 Knights - Unofficial Patch.esp [Version 1.0.9] • 39 Harvest [Flora].esp [Version 3.0.0] • 3A Harvest [Flora] - Shivering Isles.esp [Version 3.0.0] • 3B Harvest [Flora] - DLCVileLair.esp [Version 3.0.0] • 3C Harvest [Flora] - DLCFrostcrag.esp [Version 3.0.0] • 3D ActorsHaveTorches.esp • 3E Enhanced Vegetation [100%].esp • 3F tag_NaturalWildlife.esp • 40 Toggleable Quantity Prompt.esp [Version 3.1.1] • 41 Quest Award Leveller.esp • 42 Quest Award Leveller - Battlehorn Castle.esp • 43 Quest Award Leveller - Vile Lair.esp • 44 Quest Award Leveller - Mehrunes Razor.esp • 45 Quest Award Leveller - Knights of the Nine.esp • 46 RealisticForceHigh.esp • 47 RealisticMagicForceHigh.esp • 48 LightSpellWhiteDimmer.esp • 49 Stealth Entrances v1.esp • 4A RenGuardOverhaul.esp • 4B RenGuardOverhaulShiveringIsles.esp • 4C TRN One of the Gang.esp • 4D Enhanced Grabbing.esp [Version 0.4] • 4E Smarter Mercantile Leveling - Multi.esp • 4F SD Skill Diary.esp • 50 RealisticLeveling.esp • 51 All+5AttributeModifiers.esp • 52 _darker_dungeons.esp • 53 EyelashesVannilaRaces.esp • 54 _burning_kvatch.esp • 55 1310-Chamelion-NoRefraction-TESSource.esp • 56 Life Detected - OMOD.esp • 57 Real Lava 1.3.esp • 58 SwampGrass.esp • 59 fog.esp • 5A FOV Modifier.esp • 5B Blackmarket.esp • 5C Oddbasket Glass Replace ALT.esp • 5D Deadly Reflex 5 - Timed Block and 250% damage.esp • 5E DeadlyReflex 5 - Combat Moves.esp Any help would be greatly appreciated.