An infinite import loop has been detected. The following Assets were imported multiple times, but no changes to them have been detected. Please check if any custom code is trying to import them:

I have a pretty big Unity project with a lot of 3D models and upgrading the unity version is always a big problem.

I recently upgraded this project from version 2019.3.2f1 to 2020.3.6f1 and everything was working fine but I wanted to use the Play Asset Delivery, so upgraded it once again to 2020.3.28f1 and I get this error. I think it could be because of low disk space, my SSD was almost full while importing but I’m not entirely sure. I am reverting back to 2020.3.6f1 and will free some space and upgrade it once again.

Can anyone please help ?

An infinite import loop has been detected. The following Assets were imported multiple times, but no changes to them have been detected. Please check if any custom code is trying to import them:

Assets/AR/Models/Dino/Raptor/Materials/Rabtor_red.mat(modified date 2018-08-28T20:28:22.9818917Z)
Assets/Space Models/solar_system_astroid/SolarSystem/SolarSystem/solar_system_texture/solar system texture/sun/sun pattern.png(modified date 2002-04-08T06:28:30Z)
Assets/polyperfect/Low Poly Animated People/- Models/Meshes/man-basketball-player.fbx(modified date 2020-12-09T00:07:49Z)
Assets/AR/VoiceOver/fruits/pineapple.wav(modified date 2019-03-13T13:36:50Z)
Assets/Models/Farm_Food_Pack/FFP_Materials/FFP_MAT_256/FFP_MAT_DIR_radish_256.mat(modified date 2017-02-22T11:32:18Z)
Assets/Monarch/Materials/Skybox.mat(modified date 2018-08-07T12:43:05Z)
Assets/Models/BK_Food/HD_Fruits&Veggies/Models/Fruits/Lemon_01/Materials/Lemon_01.mat(modified date 2019-11-08T10:11:54.3448223Z)
Assets/Models/Animals/Animal pack deluxe/Models/Swan_goose_anim_controller.controller(modified date 2020-07-27T13:24:13.6838072Z)
Assets/Samples/Resources/HelloAR_Multi_ImageTarget/Materials/namecard.mat(modified date 2020-01-15T16:49:15.0867241Z)
Assets/Models/Mobile HQ Vehicles - Vol.1/Vehicles/Car #4/Textures/Tread_D.png(modified date 2017-12-19T02:42:56Z)
Assets/English Tracing Book/Prefabs/Effects/Sparkles.prefab(modified date 2021-10-20T08:26:32.0789637Z)
Assets/Models/ANIMALS FULL PACK/BIRDS PACK/GREAT HORNED OWL/Textures/T_GreatHornedOwl_SpecularSmoothness.tga(modified date 2018-02-04T02:19:13Z)
Assets/African Animals Big Pack/African Animal Baby Elephant (Short Version)/Textures/baby_elephant-albedo.tga(modified date 2019-08-12T12:31:59Z)
Assets/TextMesh Pro/Resources/LineBreaking Following Characters.txt(modified date 2016-04-18T23:51:28Z)
Assets/PostProcessing/Resources/Bluenoise64/LDR_LLL1_46.png(modified date 2017-05-25T15:22:19Z)
Assets/AR/VoiceOver/Space/Mars Rover.mp3(modified date 2020-08-22T19:23:28Z)
Assets/Badger/Materials/Badger_D.mat(modified date 2017-11-23T20:30:46Z)
Assets/Models/BK_Food/HD_Fruits&Veggies/Models/Vegetables/Artichoke_01/Artichoke_01_specular.png(modified date 2016-07-01T15:18:59Z)
Assets/Models/Mobile HQ Vehicles - Vol.1/Vehicles/Gas_Trailer/Textures/Truck&Bus_wheels_D.png(modified date 2017-12-19T02:40:28Z)
Assets/Spine Examples/Spine Skeletons/Gauge/Gauge_Atlas.asset(modified date 2021-08-20T07:33:28.0960536Z)
Assets/Models/Animals/ExtraModels/whale/textures/lambert1_Mixed_AO.png(modified date 2017-09-15T19:27:34Z)
Assets/AR/Models/Dino/Jurassic Pack/DinoIsland/Terrain_Trees_Details/BanyanTree.fbx(modified date 2017-12-29T17:40:11Z)
Assets/African Animals Big Pack/African Animal - Cheetah (Gepard)/Prefabs/cheeteh_sv_rm_SLP.prefab(modified date 2019-08-12T12:26:30Z)
Assets/Models/Cockroach/Cockroach_readme.txt(modified date 2017-12-26T18:56:53Z)
Assets/African Animals Big Pack/African Animal - Female Elephant/Prefabs/elephant_female_fv_ip_mat3_SHP.prefab(modified date 2019-08-12T12:26:07Z)
Assets/Models/Farm_Food_Pack/FFP_LODs/FFP_LOD_CLE_03_box_of_lettuces.prefab(modified date 2017-02-22T11:34:20Z)
Assets/English Tracing Book/Prefabs/Lowercase/z-letter-shape.prefab(modified date 2021-10-20T08:26:33.5414589Z)
Assets/AR/Models/Monuments/Polygonia_Landmarks_Separeted/Golden_Temple/Lowpoly_Golden_Temple_Images/Lowpoly_Golden_Temple_01.jpg(modified date 2019-05-13T19:50:20.7772233Z)
Assets/Models/Animals/Animal pack deluxe/Models/pike_swim_anim.FBX(modified date 2017-11-14T19:50:01Z)
Assets/polyperfect/Low Poly Animated People/- Prefabs/woman_explorer.prefab(modified date 2020-12-09T00:10:05Z)
Assets/AR/Models/Space/UFO_old.prefab(modified date 2020-08-04T19:39:51.9709671Z)
Assets/Raccoon/Animations/root-motion/raccoon@growl.FBX(modified date 2020-08-08T01:10:47Z)
Assets/Resources/Levels/Class-2/EVS/Food We Eat/Vocab/level1.txt(modified date 2018-08-05T12:23:37.1413433Z)
Assets/Moose/Animations/moose@jump.FBX(modified date 2017-12-01T18:46:35Z)
Assets/Begining Sounds Cut/u/Underwear.mp3(modified date 2021-11-01T09:03:58Z)
Assets/Sound fx/Animals/Dogs/Dogs Barking Large #6.wav(modified date 2013-12-17T22:33:11Z)
Assets/AR/Models/Helpers/TeachersFemale.prefab(modified date 2021-01-11T11:15:28.0220619Z)
Assets/Models/Animals/Animal pack deluxe/Textures/fire_salamander_nrml3.tga(modified date 2017-11-14T19:44:56Z)
Assets/JSBirds/HarpyEagle/Animations/HarpyEagleAnimationsJump.FBX(modified date 2017-04-23T05:05:43Z)
Assets/Dove/Textures/Dove_N.png(modified date 2020-01-27T11:55:02Z)
Assets/Project Whitecard/Apollo/LunarRover/Materials/Rover_Chassis2.mat(modified date 2017-05-25T15:22:35Z)
Assets/polyperfect/Low Poly Animated People/- Models/Rigs/man_clown_Rig.fbx(modified date 2020-12-09T00:08:18Z)
Assets/African Animals Big Pack/African Animal - Lion/Prefabs/Lion_SuperLowpoly.prefab(modified date 2019-08-12T12:25:36Z)
Assets/Models/Farm_Food_Pack/FFP_Prefabs/FFP_PRE_512/FFP_PRE_DIR_01_Tomato_512.prefab(modified date 2017-02-22T11:27:23Z)
Assets/Models/Farm_Food_Pack/FFP_Materials/FFP_MAT_512/FFP_MAT_CLE_wooden_box_512.mat(modified date 2017-02-22T11:43:26Z)
Assets/Resources/Levels/Class-4/EVS/States of Matter/Monkey/liquid1.png(modified date 2018-08-05T12:27:30.7537394Z)
Assets/AR/Models/Monuments/uploads_files_2427608_Taj+Mahal+obj.obj(modified date 2021-05-05T17:38:29.8942153Z)
Assets/Models/Mobile HQ Vehicles - Vol.1/Vehicles/Police_1/Materials/red.mat(modified date 2017-12-19T02:40:48Z)
Assets/Models/BK_Food/HD_Fruits&Veggies/Models/Vegetables/Turnip_01/Turnip_01_occlusion.png(modified date 2016-07-01T15:18:54Z)
Packages/com.unity.modules.unitywebrequesttexture/package.json(modified date 2022-02-02T09:19:58Z)
Assets/Sprites/Pannel Screen/Games Panel/9.png(modified date 2018-01-05T23:58:12Z)
Assets/AR/Models/Dino/Jurassic Pack/DinoIsland/Game_FX/waterplane/JPWater.shader(modified date 2017-12-30T07:32:34Z)
Assets/Models/Farm_Food_Pack/FFP_Prefabs/FFP_PRE_256/FFP_PRE_DIR_02_Bowl_of_Carrots_256.prefab(modified date 2017-02-22T11:29:04Z)
Assets/Sprites/Juniors/Screens/Activity Screen/NewSprite/cap letter1.png(modified date 2019-03-21T13:48:18Z)
Assets/activity/Space-activity/JSONS/Space Activity/SPACE_ACTIVITYWithout_SUNORBITv4/SPACE_ACTIVITY_SkeletonData.asset(modified date 2020-09-04T07:44:36.9612771Z)
Assets/African Animal - Hyena/Prefabs/hyena_sv_rm_grey_LP.prefab(modified date 2019-08-12T12:26:10Z)
Assets/English Tracing Book/Sounds/Letters Speech/F Speech.mp3(modified date 2020-08-01T11:48:55Z)
Assets/Models/Animals/Animal pack deluxe/Textures/crab_nrml8.tga(modified date 2017-11-14T19:42:41Z)
Assets/Models/Farm_Food_Pack/FFP_Models/FFP_MOD_blue_cheese_LOD2.fbx(modified date 2017-02-22T11:44:55Z)
Packages/com.unity.test-framework/CHANGELOG.md(modified date 2022-02-02T09:19:40Z)
Assets/African Animals Big Pack/African Animal - Female Elephant/Textures/diffuse_elephant_4_4k_wot.png(modified date 2019-08-12T12:36:57Z)
Assets/Australian Animals/Koala/Fbx/Materials/Koala.mat(modified date 2016-08-29T16:13:18Z)
Assets/AR/Models/Dino/Jurassic Dinosaurs Pack/Animators/PentaceratopsAC.controller(modified date 2018-08-22T10:52:30.4539179Z)
Assets/Models/BK_Food/HD_Fruits&Veggies/Models/Vegetables/Turnip_01/Turnip_01_normals.png(modified date 2016-07-01T15:15:33Z)
Assets/Sound fx/Animals/Wolf Hawling/Wolf #3.wav(modified date 2013-12-17T22:32:19Z)
Packages/com.unity.collab-proxy/Editor/PlasticSCM/Assets/Images/d_iconprivateoverlay@2x.png(modified date 2022-02-02T09:19:40Z)
Assets/JMO Assets/Cartoon FX/Textures/CFX3_T_Leaf.tga(modified date 2018-01-23T11:49:08Z)
Assets/Models/Animals/Animal pack deluxe/Materials/fire_salamander_mat.mat(modified date 2019-11-08T10:10:17.3692827Z)
Assets/African Animals Big Pack/African Animal - Wild Ass/Prefabs/Wild_Ass_Lowpoly.prefab(modified date 2019-08-12T12:38:53Z)
Assets/Hubble Telescope LOD/Textures/Hubble Telescope/LOD2/Hubble Telescope_LOD2_Interior_MetallicSmoothness.png(modified date 2019-04-16T18:49:02Z)
Assets/Models/Farm_Food_Pack/FFP_Materials/FFP_MAT_1024/FFP_MAT_CLE_broccoli_1024.mat(modified date 2017-02-22T11:48:09Z)
Assets/Mobile Puzzle Game Kit/Memory game/Animations/Game over active.anim(modified date 2019-11-08T10:12:19.5766538Z)
Assets/Models/Farm_Food_Pack/FFP_Models/FFP_MOD_milk_LOD1.fbx(modified date 2017-02-22T11:38:31Z)
Assets/Tajmahal/Texture/Minarets_texture.png(modified date 2019-06-26T10:57:47Z)
Assets/Beaver/Materials/Branch1.mat(modified date 2018-03-16T11:23:27Z)
Packages/com.unity.2d.tilemap/CHANGELOG.md(modified date 2022-02-02T09:20:02Z)
Assets/English Tracing Book/Animator/Area.controller(modified date 2021-10-20T08:26:30.1059544Z)
Assets/Editor Default Resources/Anima2D/dotRed.png(modified date 2018-11-21T04:13:53Z)
Assets/Models/Animals/ANIMALS FULL PACK/AFRICAN ANIMALS PACK/LION/FBX FILES/Lion@Walk_RM.FBX(modified date 2017-10-23T14:57:00Z)
Assets/Resources/Levels/Class-4/Maths/Subtraction/TimeAttack/level1.txt(modified date 2018-08-05T12:27:56.297338Z)
Assets/Models/Farm_Food_Pack/FFP_Prefabs/FFP_PRE_512/FFP_PRE_CLE_03_Box_of_Cabbages_512.prefab(modified date 2017-02-22T11:34:24Z)
Assets/Models/Farm_Food_Pack/FFP_Prefabs/FFP_PRE_1024/FFP_PRE_DIR_02_Bowl_of_Watermelon_slices_1024.prefab(modified date 2017-02-22T11:43:30Z)
Assets/Spine Examples/Spine Skeletons/spineboy-pro/spineboy-pro.atlas.txt(modified date 2021-08-20T07:25:09.42746Z)
Assets/Models/Stingray/source/stingray.fbx(modified date 2018-05-17T22:40:26Z)
Assets/polyperfect/Low Poly Animated People/- Sounds/crowd-walking.ogg(modified date 2020-12-09T00:10:26Z)
Assets/Models/Mobile HQ Vehicles - Vol.1/Vehicles/Car #5/Model/Car_5.FBX(modified date 2017-12-19T02:43:28Z)
Assets/polyperfect/Low Poly Animated People/- Models/Meshes/Scene/stadium-ground.fbx(modified date 2020-12-09T00:09:32Z)
Assets/Confetti FX/Demo/Materials/BackgroundDark.mat(modified date 2019-11-08T10:11:14.4578103Z)
Assets/Sprites/AR elements/Elements 1/Home Button (1).png(modified date 2019-01-20T13:33:12.9833523Z)
Assets/Space Models/SolarSystem/solar_system_texture/solar system texture/earth/earth_diffuse_night.jpg(modified date 2002-04-08T07:12:54Z)
Assets/Resources/Levels/Class-5/Maths/Multiplication/Monkey/1.png(modified date 2018-08-05T12:30:57.0884862Z)
Assets/AR/Models/Dino/Jurassic Pack/Sounds/Dime1.mp3(modified date 2017-12-29T17:39:15Z)
Assets/Models/Farm_Food_Pack/FFP_LODs/FFP_LOD_CLE_03_box_of_fruits_02.prefab(modified date 2017-02-22T11:31:56Z)
Assets/Transport Models/glider/textures/wing.png(modified date 2018-10-03T21:00:40Z)
Assets/MGTAssets/Sounds/Pairs/Hat.wav(modified date 2019-06-06T19:38:03Z)
Assets/Models/Farm_Food_Pack/FFP_Models/FFP_MOD_bagette_LOD1.fbx(modified date 2017-02-22T11:30:10Z)
Assets/Models/ANIMALS FULL PACK/BIRDS PACK/DUCK/FBX Files/Duck@IdleScratchWings.FBX(modified date 2018-02-04T02:19:40Z)
Assets/MGTAssets/CS_Assets/CS_Prefabs/Canvas/CanvasMenu.prefab(modified date 2020-09-08T13:38:47.6742516Z)
Assets/AR/Sounds/Animals/Birds/78418__stateaardvark__cockroaches.wav(modified date 2019-03-23T14:36:30.3117222Z)
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Assets/Mobile Puzzle Game Kit/Tic tac toe/Animations/Tic Tac Toe cell.controller(modified date 2019-11-08T10:12:01.458331Z)
Assets/Models/Animals/Animal pack deluxe/Textures/great_white_shark_AO2.tga(modified date 2017-11-14T19:46:51Z)
Assets/AR/Models/Dino/Jurassic Dinosaurs Pack/Texture/Torozaur/Torozaur_Height.png(modified date 2017-08-07T12:21:42Z)
Assets/Raccoon/Animations/root-motion/raccoon@seat.FBX(modified date 2020-08-08T01:11:30Z)
Packages/com.unity.collab-proxy/Editor/Collaborate/Assets/Icons/choose-mine-dark@2x.png(modified date 2022-02-02T09:19:40Z)
Assets/AR/Models/Dino/Jurassic Pack/DinoIsland/Game_FX/watercaustic/Caustic_011.png(modified date 2017-12-30T07:31:57Z)
Assets/Models/Farm_Food_Pack/FFP_Textures/FFP_TEX_1024/FFP_TEX_CLE_coconut_N_1024.tif(modified date 2017-02-22T11:42:36Z)
Assets/Game2DWaterKit/Demo/Simple Water/Sounds/Splash.mp3(modified date 2019-02-20T10:30:52Z)
Assets/AR/Models/Dino/Jurassic Pack/DinoIsland/Game_FX/watercaustic/Caustic_025.png(modified date 2017-12-30T07:33:09Z)
Assets/Models/Animals/AfricanAnimalsPack/NewModels/crocodile-animations/textures/T_CrocodileDirty_Roughness.jpg(modified date 2018-03-14T10:04:02Z)
Assets/Tracing Bundle (Assets For Children´s Games)/Tracing Shapes/Shapes/OCTAGON.png(modified date 2020-01-08T16:59:19Z)
Assets/African Animals Big Pack/African Animal Baby Elephant (Short Version)/Models/For RM_Models Animator Controller.controller(modified date 2019-08-12T12:39:43Z)
Assets/AR/Models/Dino/Jurassic Pack/DinoIsland/Game_FX/watercaustic/Caustic_049.png(modified date 2017-12-30T07:33:12Z)
Assets/activity/Space-activity/Assets/Option_1.png(modified date 2020-08-15T18:44:18Z)
Assets/AR/Models/Fruits/guava.prefab(modified date 2019-11-08T10:10:06.9939048Z)
Assets/Models/Mobile HQ Vehicles - Vol.1/Vehicles/Car #5/Materials/glass_light_lod.mat(modified date 2017-12-19T02:43:40Z)
Assets/Models/Farm_Food_Pack/FFP_Prefabs/FFP_PRE_1024/FFP_PRE_DIR_03_Box_of_Sweet_potatoes_1024.prefab(modified date 2017-02-22T11:45:11Z)
Assets/JSBirds/RedCrownedCrane/Animations/CraneAnimGlide.FBX(modified date 2017-06-24T10:57:31Z)
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Assets/Resources/Cultural/Science/PlantAnimal/Plant/grain.png(modified date 2021-09-14T09:49:12Z)
Assets/Mobile Puzzle Game Kit/Word search/UI/Word effect.prefab(modified date 2019-11-08T10:10:05.0179776Z)
Assets/Resources/Levels/mydata/Class-1/Maths/Numbers/Monkey/Images1/2 Doughnuts.png(modified date 2018-08-05T12:36:50.8631856Z)
Packages/com.unity.textmeshpro/Editor Resources/Textures/btn_AlignCapLine_Light.psd(modified date 2022-02-02T09:19:40Z)
Assets/AR/Models/Animals/sheep.prefab(modified date 2019-11-08T10:11:26.2206192Z)
Assets/Prefabs/mini 4.prefab(modified date 2019-02-13T16:13:11.8312735Z)
Assets/Sprites/MAIN GUI ELEMENTS/Buttons/Sound.png(modified date 2017-12-08T01:46:04Z)
Assets/MGTAssets/Textures/Cursor.png(modified date 2019-06-06T19:38:57Z)
Assets/Models/Farm_Food_Pack/FFP_Prefabs/FFP_PRE_512/FFP_PRE_CLE_02_Bowl_of_Mushrooms_512.prefab(modified date 2017-02-22T11:42:29Z)
Assets/African Animals Big Pack/African Animal Baby Rhino/Prefabs/BB_BabyRhino_RM_MX_SLP.prefab(modified date 2019-08-12T12:28:56Z)
Assets/DrawingAndColoring Extra/Prefabs/Group.prefab(modified date 2020-08-04T08:20:58Z)
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Assets/African Animals Big Pack/African Animal Baby Rhino/Model/For RM FBX Animator Controller.controller(modified date 2019-08-12T12:36:21Z)
Assets/Models/Animals/Animal pack deluxe/Seahorse/Prefabs/Seahorse.prefab(modified date 2019-11-08T10:09:52.4098879Z)
Assets/English Tracing Book/Prefabs/Sentences/UNCLE-sentence.prefab(modified date 2021-10-20T08:26:34.8783014Z)
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Assets/Sound fx/Animals/Pigs/Pigs Snorting.wav(modified date 2013-12-17T22:32:52Z)
Assets/Spine/Mascots/Mascot/Mascot_Atlas.asset(modified date 2021-08-20T07:33:28.1534765Z)
Assets/Meerkat/Animations/In-place/meerkat@trotright.FBX(modified date 2020-11-12T12:34:52Z)
Assets/English Tracing Book/Prefabs/Sentences/LEG-sentence.prefab(modified date 2021-11-07T13:31:04.5311912Z)
Assets/Models/Cockroach/Animations/cockroach@idle.FBX(modified date 2017-12-26T18:56:37Z)
Packages/com.unity.probuilder/Content/Icons/Toolbar/Background/Tool_Hover_Vertical_Light.png(modified date 2020-02-12T11:33:04Z)
Assets/Sprites/Juniors/Characters/Bear/Sprite/Hand Left.png(modified date 2018-12-06T16:29:30Z)
Assets/woodlandAnimalPack/skunk/skunk@die.FBX(modified date 2015-02-12T01:41:30Z)
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Assets/Models/Mobile HQ Vehicles - Vol.1/Vehicles/Car #2/Materials/glass_light.mat(modified date 2017-12-19T02:36:03Z)
Assets/Models/Animals/Animal pack deluxe/Seahorse/Models/Material<message truncated>

Hi VERY IMPORTANT First of All before any step just make a copy of your project folder.
For me one of the assets caused the loop. Reimport didn’t work. What I did I deleted the folder of the asset that caused the problem. Then I reimported all assets. At the end I imported the asset again that caused the problem.

Hi all! I started getting the error (An infinite import loop has been detected. The following Assets were imported multiple times, but no changes to them have been detected. Please check if any custom code is trying to import them: …) on a fully working project yesterday. The complete removal of the “Library” folder from the project folder helped.

It’s a bit of a necropost here, but I got the same error just now (on 2021.3.6) and the reason was a broken symlink in my Assets folder.

After removing the link the errors disappeared; just in case it might help someone else.

Assets → Reimport All fixed it for me!

The sadness is when you are in Safe Mode and even unable to exit to do reimport all. I am crying.