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I've updated my developer tools in Windows 11 to use the updated .NET 9/10 of November 2025 update. I have not updated my projects to .NET 10, so the projects are running in .NET 9. I have one project in an asp .net core web project that errors out and won't run. The error message is below. I've tried to clean and rebuild with no luck. I'm really lost on this one. The error happens in VS 2022 and 2026. Looks like the error is in the area of the bootstrap-table, but I am not sure what to do. Suggestions?

Conflicting assets with the same target path 'lib/bootstrap-table/extensions/page-jump-to/bootstrap-table-page-jump-to#[.{fingerprint=r36w8umzuk}]?.css.gz'. For assets 'Identity: C:\SoftwareSource\FSM Client Portal\Portal\PortalAdmin\obj\Debug\net9.0\compressed\00a8xcg4nf-{0}-r36w8umzuk-r36w8umzuk.gz, SourceType: Discovered, SourceId: PortalAdmin, ContentRoot: C:\SoftwareSource\FSM Client Portal\Portal\PortalAdmin\obj\Debug\net9.0\compressed\, BasePath: /, RelativePath: lib/bootstrap-table/extensions/page-jump-to/bootstrap-table-page-jump-to#[.{fingerprint=r36w8umzuk}]?.css.gz, AssetKind: All, AssetMode: All, AssetRole: Alternative, AssetRole: , AssetRole: , RelatedAsset: C:\SoftwareSource\FSM Client Portal\Portal\PortalAdmin\wwwroot\lib\bootstrap-table\extensions\page-jump-to\bootstrap-table-page-jump-to.css, AssetTraitName: Content-Encoding, AssetTraitValue: gzip, Fingerprint: fzncack1z2, Integrity: a36f6N6Xb2sM/f42QUO6AnonsJ3E3Zf3EpvvWP73cdc=, FileLength: 180, LastWriteTime: 11/13/2025 7:05:14 PM +00:00, CopyToOutputDirectory: Never, CopyToPublishDirectory: PreserveNewest, OriginalItemSpec: C:\SoftwareSource\FSM Client Portal\Portal\PortalAdmin\wwwroot\lib\bootstrap-table\extensions\page-jump-to\bootstrap-table-page-jump-to.css' and 'Identity: C:\SoftwareSource\FSM Client Portal\Portal\Portal\obj\Debug\net9.0\compressed\n8aecfvmxt-{0}-r36w8umzuk-r36w8umzuk.gz, SourceType: Project, SourceId: Portal, ContentRoot: C:\SoftwareSource\FSM Client Portal\Portal\Portal\obj\Debug\net9.0\compressed\, BasePath: /, RelativePath: lib/bootstrap-table/extensions/page-jump-to/bootstrap-table-page-jump-to#[.{fingerprint=r36w8umzuk}]?.css.gz, AssetKind: All, AssetMode: All, AssetRole: Alternative, AssetRole: , AssetRole: , RelatedAsset: C:\SoftwareSource\FSM Client Portal\Portal\Portal\wwwroot\lib\bootstrap-table\extensions\page-jump-to\bootstrap-table-page-jump-to.css, AssetTraitName: Content-Encoding, AssetTraitValue: gzip, Fingerprint: fzncack1z2, Integrity: a36f6N6Xb2sM/f42QUO6AnonsJ3E3Zf3EpvvWP73cdc=, FileLength: 180, LastWriteTime: 11/13/2025 7:05:06 PM +00:00, CopyToOutputDirectory: Never, CopyToPublishDirectory: PreserveNewest, OriginalItemSpec: C:\SoftwareSource\FSM Client Portal\Portal\Portal\wwwroot\lib\bootstrap-table\extensions\page-jump-to\bootstrap-table-page-jump-to.css' from different projects.

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    I think it's not ASP.NET related, did you try to run the app with dotnet run / dotnet build ? I think they should give similiar results. Maybe try cleaning you node packages and reinstalling them? Commented Nov 14 at 11:02
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    the error seems to be related to bootstrap-table, not bootstrap, and I think this is the important part you should start from: Conflicting assets with the same target path: stackoverflow.com/… Commented Nov 14 at 18:38
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    @traynor thanks for the link, I had found them but never had any success with the easy solutions. Hoping this might be solved with an update to .NET 10, but no love there. In reading the error more, it seems to be complaining about a reference to the "Identity." I'm guessing that is due to the identity section added into the project. Commented Nov 14 at 21:46
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    The error says your Javascript libraries are mixed up. Not .NET 10 packages. We can't guess how your project is set up, or what custom settings or target paths are using .NET 9 isn't .NET 10, and they aren't broken. If something changed in November, check your version history Commented Nov 15 at 11:07
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    If you search for the error message Conflicting assets with the same target path you'll find similar if not actually duplicate questions. The problem is always the same. Somehow, somewhere, a change ended up causing multiple files to have the same target path Commented Nov 15 at 11:19

3 Answers 3

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This is a common issue with the new .NET 9/10 static web asset compression feature where multiple projects have conflicting assets with the same output path. The error shows that both PortalAdmin and Portal projects are trying to output the same bootstrap-table CSS file to the same compressed location.

Add this to your project file(s) to disable the new compression feature:

<PropertyGroup>
    <EnableStaticWebAssetCompression>false</EnableStaticWebAssetCompression>
</PropertyGroup>

You can add this to both PortalAdmin.csproj and Portal.csproj files.

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1 Comment

Thank you for your suggestion. I tried the suggestions and that did not solve the problem.
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I'm not sure if this was a great solution, but it is what I went with.

The <EnableStaticWebAssetCompress/> tag didn't help..

I uninstalled the js libraries I had installed that were listed as conflicts. there were now new conflicts with the existing libraries.

I renamed the folders with the existing libraries.

I added the libraries off of a cdn, instead of running them locally. I don't think that this is absolutely required as I could have run from the renamed libraries.

Many thanks to everyone that helped. :-)

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-1

You’re running into a new .NET 9/10 static web assets compression feature, not a Bootstrap bug.

he new SDK pre-compresses static files (creates .gz versions) under obj...\compressed.

You have two web projects – Portal and PortalAdmin – and they both contain the same file:

wwwroot\lib\bootstrap-table\extensions\page-jump-to\bootstrap-table-page-jump-to.css

<PropertyGroup>
  <EnableStaticWebAssetCompression>false</EnableStaticWebAssetCompression>
</PropertyGroup>

to

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
    <EnableStaticWebAssetCompression>false</EnableStaticWebAssetCompression>
  </PropertyGroup>

  <!-- the rest of your project file -->
</Project>
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1 Comment

Thank you for your suggestion. That did not solve the problem.

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