Steps to reproduce:

1. Create a Unity project
2. Click the "AI" button
3. Click "Agree and install Unity AI"
4. When the installation is complete, go to "AI-> Generate New ->Material"
5. Observe that the "Generate" button is displayed as disabled in the "Generate" tab
6. Select "Upscale" tab
7. Observe that the "Upscale" button is displayed as active, click it
8. Observe the result

Actual results: Console displays errors
{code:java}
ArgumentNullException: Value cannot be null.
Parameter name: imageStream {code}
{code:java}
ArgumentNullException: Generation request failed and download cannot proceed.
Parameter name: arg {code}
Expected results: Button should be disabled. No errors in the Console view

Reproducible with versions: 1.7.0-pre.1(6000.3.10f1, 6000.4.0b10, 6000.5.0a8)

Not reproducible with versions: -

Tested on (OS): macOS - Tahoe 26.3

Notes: The same issue exists with the "Generate PBR" button. Adding full errors
{code:java}
ArgumentNullException: Value cannot be null.
Parameter name: imageStream
Unity.AI.Generators.IO.Utilities.ImageFileUtilities.HasPngAlphaChannel (System.IO.Stream imageStream) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.IO/Utilities/ImageFileUtilities.cs:410)
Unity.AI.Pbr.Services.Stores.Selectors.Selectors.SelectReferenceAssetStreamWithFallback (Unity.AI.Generators.Redux.IState state, Unity.AI.Toolkit.Asset.AssetReference asset) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Selectors/GenerationSettingsSelectors.cs:314)
Unity.AI.Pbr.Services.Stores.Selectors.Selectors.SelectPromptAssetBytesWithFallback (Unity.AI.Generators.Redux.IState state, Unity.AI.Toolkit.Asset.AssetReference asset) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Selectors/GenerationSettingsSelectors.cs:379)
Unity.AI.Pbr.Services.Stores.Actions.Backend.Generation.PromptAssetStream (Unity.AI.Generators.Redux.IState state, Unity.AI.Toolkit.Asset.AssetReference asset) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/Backend/Generation.cs:859)
Unity.AI.Pbr.Services.Stores.Actions.Backend.Generation.UploadReferencesAsync (Unity.AI.Toolkit.Asset.AssetReference asset, Unity.AI.Pbr.Services.Stores.States.RefinementMode refinementMode, Unity.AI.Pbr.Services.Stores.States.PatternImageReference patternImageReference, Unity.AI.Generators.Redux.Thunks.AsyncThunkApi`1[TPayload] api) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/Backend/Generation.cs:455)
Unity.AI.Pbr.Services.Stores.Actions.Backend.Generation.GenerateMaterialsAsync (Unity.AI.Pbr.Services.Stores.Actions.Payloads.GenerateMaterialsData arg, Unity.AI.Generators.Redux.Thunks.AsyncThunkApi`1[TPayload] api) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/Backend/Generation.cs:106)
UnityEngine.Debug:LogException(Exception)
Unity.AI.Pbr.Services.Stores.Actions.Backend.<GenerateMaterialsAsync>d__0:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/Backend/Generation.cs:121)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1:Start(<GenerateMaterialsAsync>d__0&)
Unity.AI.Pbr.Services.Stores.Actions.Backend.Generation:GenerateMaterialsAsync(GenerateMaterialsData, AsyncThunkApi`1)
Unity.AI.Pbr.Services.Stores.Actions.<GenerateMaterialsMainWithArgsAsync>d__38:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/GenerationResultsActions.cs:411)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1:Start(<GenerateMaterialsMainWithArgsAsync>d__38&)
Unity.AI.Pbr.Services.Stores.Actions.GenerationResultsActions:GenerateMaterialsMainWithArgsAsync(GenerationArgs, AsyncThunkApi`1)
Unity.AI.Generators.Redux.Thunks.<<-ctor>b__0>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkCreator.cs:50)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1:Start(<<-ctor>b__0>d&)
Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass0_0:<.ctor>b__0(GenerationArgs, AsyncThunkApi`1)
Unity.AI.Generators.Redux.Thunks.<<Invoke>b__0>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/BaseAsyncThunkCreator.cs:52)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Invoke>b__0>d&)
Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass17_0:<Invoke>b__0(IStoreApi)
Unity.AI.Generators.Redux.Thunks.<<get_Middleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/ThunkMiddleware.cs:12)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_Middleware>b__2>d&)
Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass1_1:<get_Middleware>b__2(Object)
Unity.AI.Pbr.Services.SessionPersistence.<<get_PersistenceMiddleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/SessionPersistence/SharedStore.cs:37)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_PersistenceMiddleware>b__2>d&)
Unity.AI.Pbr.Services.SessionPersistence.<>c__DisplayClass4_1:<get_PersistenceMiddleware>b__2(Object)
Unity.AI.ModelSelector.Services.Stores.Middleware.<<Create>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.ModelSelector/Services/Stores/Middleware/FilterCacheClearingMiddleware.cs:13)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Create>b__2>d&)
Unity.AI.ModelSelector.Services.Stores.Middleware.<>c__DisplayClass0_0:<Create>b__2(Object)
Unity.AI.Generators.Redux.StoreApi:DispatchAction(Object) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/StoreApi.cs:21)
Unity.AI.Generators.Redux.Thunks.AsyncThunkApi`1:DispatchAction(Object) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkApi.cs:12)
Unity.AI.Generators.Redux.Thunks.AsyncThunkExtensions:Dispatch(IStoreApi, ICreateAsyncThunk`1, GenerationArgs, CancellationToken) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkExtensions.cs:23)
Unity.AI.Pbr.Services.Stores.Actions.<<-cctor>b__41_5>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/GenerationResultsActions.cs:393)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<-cctor>b__41_5>d&)
Unity.AI.Pbr.Services.Stores.Actions.<>c:<.cctor>b__41_5(AssetReference, AsyncThunkApi`1)
Unity.AI.Generators.Redux.Thunks.<<-ctor>b__0>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkCreator.cs:50)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1:Start(<<-ctor>b__0>d&)
Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass0_0:<.ctor>b__0(AssetReference, AsyncThunkApi`1)
Unity.AI.Generators.Redux.Thunks.<<Invoke>b__0>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/BaseAsyncThunkCreator.cs:52)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Invoke>b__0>d&)
Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass17_0:<Invoke>b__0(IStoreApi)
Unity.AI.Generators.Redux.Thunks.<<get_Middleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/ThunkMiddleware.cs:12)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_Middleware>b__2>d&)
Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass1_1:<get_Middleware>b__2(Object)
Unity.AI.Pbr.Services.SessionPersistence.<<get_PersistenceMiddleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/SessionPersistence/SharedStore.cs:37)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_PersistenceMiddleware>b__2>d&)
Unity.AI.Pbr.Services.SessionPersistence.<>c__DisplayClass4_1:<get_PersistenceMiddleware>b__2(Object)
Unity.AI.ModelSelector.Services.Stores.Middleware.<<Create>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.ModelSelector/Services/Stores/Middleware/FilterCacheClearingMiddleware.cs:13)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Create>b__2>d&)
Unity.AI.ModelSelector.Services.Stores.Middleware.<>c__DisplayClass0_0:<Create>b__2(Object)
Unity.AI.Generators.Redux.StoreApi:DispatchAction(Object) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/StoreApi.cs:21)
Unity.AI.Generators.Redux.Thunks.AsyncThunkExtensions:Dispatch(IStoreApi, ICreateAsyncThunk`1, AssetReference, CancellationToken) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkExtensions.cs:23)
Unity.AI.Pbr.Components.GenerateButton:OnGenerate() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Components/GenerateButton/GenerateButton.cs:135)
UnityEditor.GUIView:ProcessEvent(EntityId, IntPtr, Boolean&) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUIView.cs:70)
{code}
{code:java}
ArgumentNullException: Generation request failed and download cannot proceed. Parameter name: arg Unity.AI.Pbr.Services.Stores.Actions.GenerationResultsActions.DownloadMaterialsMainAsync (Unity.AI.Pbr.Services.Stores.Actions.Payloads.DownloadMaterialsData arg, Unity.AI.Generators.Redux.Thunks.AsyncThunkApi`1[TPayload] api) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/GenerationResultsActions.cs:438) Unity.AI.Pbr.Services.Stores.Actions.GenerationResultsActions.GenerateMaterialsMainWithArgsAsync (Unity.AI.Generators.UI.Payloads.GenerationArgs payload, Unity.AI.Generators.Redux.Thunks.AsyncThunkApi`1[TPayload] api) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/GenerationResultsActions.cs:414) Unity.AI.Generators.Redux.Thunks.AsyncThunkCreatorWithArg`1+<>c__DisplayClass0_0[TArg].<.ctor>b__0 (TArg arg, Unity.AI.Generators.Redux.Thunks.AsyncThunkApi`1[TPayload] api) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkCreator.cs:50) Unity.AI.Generators.Redux.Thunks.BaseAsyncThunkCreator`2+<>c__DisplayClass17_0[TArg,TPayload].<Invoke>b__0 (Unity.AI.Generators.Redux.IStoreApi api) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/BaseAsyncThunkCreator.cs:52) UnityEngine.Debug:LogException(Exception) Unity.AI.Generators.Redux.Thunks.<<Invoke>b__0>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/BaseAsyncThunkCreator.cs:70) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Invoke>b__0>d&) Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass17_0:<Invoke>b__0(IStoreApi) Unity.AI.Generators.Redux.Thunks.<<get_Middleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/ThunkMiddleware.cs:12) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_Middleware>b__2>d&) Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass1_1:<get_Middleware>b__2(Object) Unity.AI.Pbr.Services.SessionPersistence.<<get_PersistenceMiddleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/SessionPersistence/SharedStore.cs:37) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_PersistenceMiddleware>b__2>d&) Unity.AI.Pbr.Services.SessionPersistence.<>c__DisplayClass4_1:<get_PersistenceMiddleware>b__2(Object) Unity.AI.ModelSelector.Services.Stores.Middleware.<<Create>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.ModelSelector/Services/Stores/Middleware/FilterCacheClearingMiddleware.cs:13) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Create>b__2>d&) Unity.AI.ModelSelector.Services.Stores.Middleware.<>c__DisplayClass0_0:<Create>b__2(Object) Unity.AI.Generators.Redux.StoreApi:DispatchAction(Object) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/StoreApi.cs:21) Unity.AI.Generators.Redux.Thunks.AsyncThunkApi`1:DispatchAction(Object) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkApi.cs:12) Unity.AI.Generators.Redux.Thunks.AsyncThunkExtensions:Dispatch(IStoreApi, ICreateAsyncThunk`1, GenerationArgs, CancellationToken) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkExtensions.cs:23) Unity.AI.Pbr.Services.Stores.Actions.<<-cctor>b__41_5>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/Stores/Actions/GenerationResultsActions.cs:393) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<-cctor>b__41_5>d&) Unity.AI.Pbr.Services.Stores.Actions.<>c:<.cctor>b__41_5(AssetReference, AsyncThunkApi`1) Unity.AI.Generators.Redux.Thunks.<<-ctor>b__0>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkCreator.cs:50) System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1:Start(<<-ctor>b__0>d&) Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass0_0:<.ctor>b__0(AssetReference, AsyncThunkApi`1) Unity.AI.Generators.Redux.Thunks.<<Invoke>b__0>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/BaseAsyncThunkCreator.cs:52) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Invoke>b__0>d&) Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass17_0:<Invoke>b__0(IStoreApi) Unity.AI.Generators.Redux.Thunks.<<get_Middleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/ThunkMiddleware.cs:12) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_Middleware>b__2>d&) Unity.AI.Generators.Redux.Thunks.<>c__DisplayClass1_1:<get_Middleware>b__2(Object) Unity.AI.Pbr.Services.SessionPersistence.<<get_PersistenceMiddleware>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Services/SessionPersistence/SharedStore.cs:37) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<get_PersistenceMiddleware>b__2>d&) Unity.AI.Pbr.Services.SessionPersistence.<>c__DisplayClass4_1:<get_PersistenceMiddleware>b__2(Object) Unity.AI.ModelSelector.Services.Stores.Middleware.<<Create>b__2>d:MoveNext() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.ModelSelector/Services/Stores/Middleware/FilterCacheClearingMiddleware.cs:13) System.Runtime.CompilerServices.AsyncTaskMethodBuilder:Start(<<Create>b__2>d&) Unity.AI.ModelSelector.Services.Stores.Middleware.<>c__DisplayClass0_0:<Create>b__2(Object) Unity.AI.Generators.Redux.StoreApi:DispatchAction(Object) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/StoreApi.cs:21) Unity.AI.Generators.Redux.Thunks.AsyncThunkExtensions:Dispatch(IStoreApi, ICreateAsyncThunk`1, AssetReference, CancellationToken) (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Generators.Redux/Thunks/AsyncThunkExtensions.cs:23) Unity.AI.Pbr.Components.GenerateButton:OnGenerate() (at ./Library/PackageCache/com.unity.ai.generators@2fa83e7522a1/Modules/Unity.AI.Pbr/Components/GenerateButton/GenerateButton.cs:135) UnityEditor.GUIView:ProcessEvent(EntityId, IntPtr, Boolean&) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUIView.cs:70)
{code}