Power Bi Report Server May 2025 Errors

[KenCBowman]

I upgraded my Windows Server 2019 from Power BI Report Server (May 2024) to Power BI Report Server (May 2025) and am now seeing the following errors in the browser's console:

• https://dev.my-site.com/powerbi/libs/scripts/styleLibrary.js net::ERR_ABORTED 404 (Not Found) - 
• Refused to execute script from 'https://dev.my-site.com/powerbi/libs/scripts/styleLibrary.js' because its MIME type ('') is not executable, and strict MIME type checking is enabled.
• ERROR NullInjectorError: R3InjectorError(u)[InjectionToken CopilotCapabilityService -> InjectionToken AgentMetadataService -> InjectionToken PBICopilotProxy -> InjectionToken PBICopilotProxy]:
  NullInjectorError: No provider for InjectionToken PBICopilotProxy! http://atlassql3/powerbi/libs/scripts/reportServerHostModern.js

These errors were not occurring in the May 2024 version. I've tried clearing the browser's cache, repairing the Power BI Report Server install and rebooting the server multiple times.

Any help in resolving these issues would be greatly appreciated.

Thanks,

Ken

[Pascalw]

Hi,

I have the exact same issue with May 2024 release. It is a fresh install not an upgrade.

Repair don't fix the issue.

 styleLibrary.js and other .js files are not physically stored on the Hard drive of the server.

PBIRS is not using a classic iis instance like Shahed Shaikh say, it have his proper Web Host (HttpListener).

There is no way to disable Copilot functionnality as well ...

Have you found a way to fix the issue?

Thanks.

Pascal

[v-ssriganesh]

Hello @KenCBowman,

We are following up once again regarding your query. Could you please confirm if the issue has been resolved through the support ticket with Microsoft?

If the issue has been resolved, we kindly request you to share the resolution or key insights here to help others in the community. 

Thank you.

[KenCBowman]

No its not. Our licensing of Power BI Report Server (PBIRS) is through SQL Server Enterprise Core licensing with SA. We do not have a Premier or Unified Support contract. We also do not have need for Fabric Licensing for our on prem PBIRS (whose support ticket process/form seems to have no relevance to issues with PBIRS).

[v-ssriganesh]

Hello @KenCBowman,
Thanks for the clarification. In this case, since support for PBIRS requires the appropriate licensing/support contract, you may need to take the help of your colleagues or someone in your organization who has the required support plan to raise a Microsoft support ticket on your behalf. This will ensure the issue is investigated by the support team.

Best regards,
Ganesh Singamshetty

[KenCBowman]

We tried upgrading another Windows 2019 server from Power BI Report Server (May 2024) to the May 2025 version sequentially (i.e., upgraded to the September 2024 version, then January 2025 version and finally May 2025 version).

Testing the Power BI reports between each upgrade resulted in no issues until we upgraded to the May 2025 version. Same errors are appearing on this server as mentioned in my original post.

So it appears sequentially upgrading through each version resulted in the same errors occurring in the browser's console.

[Shahid12523]

After upgrading to Power BI Report Server (May 2025), you're seeing:
404 error for styleLibrary.js — file not found or MIME type misconfigured
Angular injection error for PBICopilotProxy — likely due to missing Copilot services

Quick Fixes:
Check if styleLibrary.js exists and is served with correct MIME type (application/javascript)
Ensure reportServerHostModern.js loads properly
Disable Copilot features if not supported in your setup
Review IIS and server config for missing assets or MIME settings

[KenCBowman]

Hi Shahed,

We continue to receive the following errors even for the simplest Power BI reports after upgrading to Power BI Report Server (May 2025).

We've tried running Repair multiple times, examined the Report Server and Event logs for any errors, reviewed the Report Server configuraiton files, etc., none of which has given us any clue as to how to fix the errors.

I assume the MIME issue is related to styleLibrary.js not existing. Is there somewhere on my physical server to look for the existence of this file?

I would happily disable Copilot features in Power BI Report Server. How do I do that?

Thanks,

Ken

[KenCBowman]

Additional info: these errors only appear in the console when opening a Power BI report saved using Power BI Desktop (May 2025) for Report Server.

[v-ssriganesh]

Hello @KenCBowman,
Thank you for reaching out to the Microsoft Fabric Community Forum. The errors are likely due to incomplete deployment of static resources or missing Copilot-related services introduced in the May 2025 release.

Please consider the below points:

•  Re-run the May 2025 installer and choose repair to ensure all files are correctly deployed. Upgrade Power BI Report Server
• Check that styleLibrary.js exists in the libs/scripts folder and is served with the correct MIME type (application/javascript). Adding Static Content MIME Mappings <mimeMap> | Microsoft Learn
• The May 2025 release includes Copilot features. Make sure all required services and dependencies are properly configured. Power BI Report Server May 2025 Release Notes

If you have any further questions, please don't hesitate to contact us through the community. We are happy to assist you.

Best Regards,
Ganesh singamshetty.

[KenCBowman]

As I mentioned, I have already tried reinstalling and it did not fix the errors. Despite these errors, all of my reports work fine, but I'd like to resolve these errors becasue something is clearly wrong with the install.

Where do I find styleLibrary.js in the folder structure on the harddrive (did this file exist in the May 2024 release)? I assume the mime issue is related to the file not existing. 

I didn not see any special references in your link to services and dependencies required by Copilot. What are those?

Thanks,

Ken

[v-ssriganesh]

Hi @KenCBowman,
We regret the inconvenience caused. Please consider raising a Microsoft support ticket for further investigation. You can explain all the troubleshooting steps you have taken to help them better understand the issue.

You can create a Microsoft support ticket with the help of the link below:
https://learn.microsoft.com/en-us/power-bi/support/create-support-ticket

Best Regards,
Ganesh singamshetty.