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Completed
Last Updated: 18 Jun 2026 08:30 by ADMIN
Release 2024 Q3 (Aug)
Bill
Created on: 15 May 2024 10:44
Category: UI for ASP.NET MVC
Type: Bug Report
4
Bundling the kendo js files results in an error

Bug report

Bundling the Kendo js files in an ASP.NET MVC application throws a NullReferenceException error. Reproduced with versions 2024.1.319 and 2024.2.514. The bundling works without exceptions in version 2023.3.1114.

Reproduction of the problem

  1. Add the following bundle to the BundleConfig.cs file:
bundles.Add(new ScriptBundle("~/bundles/kendo").Include(
        "~/Scripts/kendo/2024.2.514/kendo.web.min.js",
        "~/Scripts/kendo/2024.2.514/kendo.aspnetmvc.min.js"
));

Instead of kendo.web.min.js you can use kendo.all.min.js with the same result.

  1. Render the scripts in the _Layout.cshtml's head element after jQuery by calling:
@Scripts.Render("~/bundles/kendo")

Current behavior

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Workaround:

Use bundles.Add(new Bundle("~/bundles/kendo") instead of bundles.Add(new ScriptBundle("~/bundles/kendo")

Expected/desired behavior

No exception is thrown when bundling the Kendo script files.

Environment

  • Kendo UI version: 2024.2.514
  • jQuery version: x.y
  • Browser: [all ]
6 comments
ADMIN
Viktor Tachev
Posted on: 18 Jun 2026 08:30

Hi Simon,

Thank you for clarifying the product versions in which the error occurs.

The issue is caused by limitations of the MVC Bundler (and similarly, older versions of webpack), which cannot properly process some of the modern JavaScript features used in recent Kendo UI releases. In addition, the bundling process attempts to minify files that are already minified, which can lead to further issues.

If your goal is to reduce the size of the client-side resources, I recommend considering the approach described in the following article:

https://www.telerik.com/aspnet-mvc/documentation/installation/adding-client-side-resources/ecmascript

Another option is to generate custom scripts that include only the resources required by the components used in your application. This can be achieved with our Kendo CLI tool. Additional information is available here:

https://www.telerik.com/kendo-jquery-ui/documentation/intro/installation/custom-builder-cli

That said, you may also try one of the following workarounds. Please note that, due to the MVC Bundler limitations mentioned above, their effectiveness cannot be guaranteed.

  • Replace new ScriptBundle() with new Bundle() in the BundleConfig, as per the example below:
bundles.Add(new Bundle("~/bundles/kendo").Include(
	"~/Scripts/kendo/2026.1.212/kendo.all.min.js",
	"~/Scripts/kendo/2026.1.212/kendo.aspnetmvc.min.js"));
  • Disable minification for the scripts:
bundles.Add(new ScriptBundle("~/bundles/kendo").Include(
    "~/Scripts/kendo/2026.1.212/kendo.all.min.js"
));
// Disable minification for this bundle
BundleTable.EnableOptimizations = false;

 

    Regards,
    Viktor Tachev
    Progress Telerik

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    Simon
    Posted on: 11 Jun 2026 16:02

    Hi

    This error is happening in version 2026.1.212, and later versions.

    The bundling works without exceptions in version 2025.4.1321.

    ADMIN
    Eyup
    Posted on: 30 Sep 2024 16:46

    Hello Kyle,

     

    I got a response from the QA team and it turns out that the issue was discussed and completed.

    Additional details on the matter you can find here:
    https://github.com/telerik/kendo-ui-core/issues/7828#issuecomment-2165912233

    I hope you will find this info helpful.

     

    Regards,
    Eyup
    Progress Telerik

    Love the Telerik and Kendo UI products and believe more people should try them? Invite a fellow developer to become a Progress customer and each of you can get a $50 Amazon gift voucher.

    ADMIN
    Eyup
    Posted on: 30 Sep 2024 15:13

    Hello Kyle,

     

    Thank you for reminding us about this issue.

    There is no progress on that front and I hope the workaround works for you.

    I will escalate this item to our QA engineers.

     

    Regards,
    Eyup
    Progress Telerik

    Love the Telerik and Kendo UI products and believe more people should try them? Invite a fellow developer to become a Progress customer and each of you can get a $50 Amazon gift voucher.

    Kyle
    Posted on: 24 Sep 2024 01:20
    I'm using kendo.all.min.js.
    Kyle
    Posted on: 24 Sep 2024 01:19
    This is still happening in 2024.3.806. Has there been any update on this?
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