So I decided to download many recommended mods, and so far they all worked - however, certain mods cause Oblivion to have "an error has occurred", disallowing me to exit the game properly and even leave the tutorial sewers. I was able to "single" them out, and apparently Better Cities and the Unique Landscape set mods are causing it. Here's my loadout, for those who are interested (already had BOSS sorted it out): Oblivion.esm Jog_X_Mod.esm Francesco's Leveled Creatures-Items Mod.esm Francesco's Optional New Items Add-On.esm Francesco's Optional New Creatures Add-On.esm Harvest[Containers].esm Harvest[Containers] - Flat-Top Barrels Add-on.esm Harvest[Containers] - Havok Crates Add-on.esm Harvest[Containers] - Player Home Add-on.esm Better Cities Resources.esm Unofficial Oblivion Patch.esp DLCShiveringIsles.esp Unofficial Shivering Isles Patch.esp Better Cities .esp IlluminationWithin.esp ClocksOfCyrodiil.esp ClocksOfCyrodiil_BC_OBC_OC_OCLR_Vanilla.esp Harvest[Containers] - SI - Ore Respawn.esp Harvest[Containers] - Vanilla - Ore Respawn.esp Harvest[Containers] - Player Home Add-on.esp Harvest[Containers] - Flat-Top Barrels Add-on.esp Harvest[Containers] - Havok Crates Add-on.esp DLCHorseArmor.esp DLCHorseArmor - Unofficial Patch.esp DLCOrrery.esp DLCOrrery - Unofficial Patch.esp DLCVileLair.esp DLCVileLair - Unofficial Patch.esp DLCMehrunesRazor.esp DLCMehrunesRazor - Unofficial Patch.esp DLCSpellTomes.esp DLCSpellTomes - Unofficial Patch.esp MaleBodyReplacerV4.esp DLCThievesDen.esp DLCThievesDen - Unofficial Patch.esp DLCThievesDen - Unofficial Patch - SSSB.esp Francesco's Optional Files.esp Abriael_Human.esp Scribe Supplies.esp thievery.esp VaultsofCyrodiil.esp VaultsofCyrodiilBC.esp za_bankmod.esp DLCBattlehornCastle.esp DLCBattlehornCastle - Unofficial Patch.esp DLCFrostcrag.esp DLCFrostcrag - Unofficial Patch.esp Knights.esp Knights - Unofficial Patch.esp xuldarkforest.esp xulTheHeath.esp xulFallenleafEverglade.esp xulColovianHighlands_EV.esp xulChorrolHinterland.esp xulBeachesOfCyrodiilLostCoast.esp xulBravilBarrowfields.esp xulLushWoodlands.esp xulAncientYews.esp xulAncientRedwoods.esp xulCloudtopMountains.esp xulArriusCreek.esp xulRollingHills_EV.esp xulRiverEthe.esp xulBrenaRiverRavine.esp xulImperialIsle.esp xulBlackwoodForest.esp xulCheydinhalFalls.esp xulAspenWood.esp xulSkingradOutskirts.esp JQ-Fighters_Guild_United.esp Harvest [Flora].esp Harvest [Flora] - Shivering Isles.esp Harvest [Flora] - DLCVileLair.esp Harvest [Flora] - DLCFrostcrag.esp StealthOverhaul.esp No psychic guards v1.2.esp Let There Be Darkness - Cyrodiil.esp Let There Be Darkness - Cyrodiil + SI.esp Let There Be Darkness - Knights.esp Let There Be Darkness - Mehrunes Razor.esp KT_CustomRaceFix.esp Better Cities Full.esp Better Cities - Unique Landscape Barrowfields.esp Better Cities - Unique Landscape Chorrol Hinterland.esp Better Cities - Unique Landscape Cheydinhal Falls.esp Better Cities - No LEYAWIIN Flooding.esp Better Cities - Unique Landscape Skingrad Outskirts.esp Better Cities - Thievery.esp Better Cities - VWD of the IC.esp Better Imperial City.esp Francesco's 7 days respawn time.esp NPCHelms.esp FasterMercantileLevelingV1.1.esp