So what or where at what site is this happening? You give no screenshot error or URL site for other to verify what is going on here.

Firefox doesn't have a limit for downloading a large file, so if this isn't working then possibly other (security/AV) software is interfering.

It is possible that (anti-virus) security software is causing the problem. Try to disable security software temporarily to see if that makes a difference.

I'm not the only one with this problem. Google search reports more cases with the same problem.

In my case the URL is a private space in the Microsoft cloud sharepoint.com. So you can't verifiy the problem with this source. I made a download of "ubuntu 23.04 desktop amd64.iso". The 4.8 GB could be successfully downloaded. Maybe it is possible that the microsoft cloud checks the browser and if it is not the Edge browser they are killing the session after 1 GB? Rem: Stopping the transfer doesn't create any fault message. Transferring data greater 1 GB from sharepoint with Edge are successfull.

thanks with kind regards.

It may be a similar case, and a temporary solution is shared with you. It may require professional developers to follow up and handle the issue in the future.

Problem Description Issue: Users experience interrupted downloads when using Firefox to download large files from SharePoint, particularly under slower network speeds. This issue does not occur in Chrome under identical network and device conditions.

Solution Debugging and Resolution:

Initial Observation: Utilized Firefox's debugging tools to monitor and analyze the download process. Downloads were failing in Firefox with an error message indicating a ServiceWorker issue: "Failed to load ‘’. A ServiceWorker intercepted the request and encountered an unexpected error.". Key Action: Unregistered SharePoint ServiceWorkers within Firefox. Outcome: Subsequent tests showed no interruptions in the download process, confirming that ServiceWorkers were the root cause of the problem.

Analysis of Potential Causes Different Handling of ServiceWorkers:Browsers' Diverse Strategies: Various browsers have distinct policies and methods for managing ServiceWorkers. Firefox's Specifics: Firefox may implement stricter security measures or different handling mechanisms that are not compatible with SharePoint's ServiceWorker configurations, leading to download interruptions.

Recommendations For Users: Temporarily unregister ServiceWorkers in Firefox if encountering similar download issues with SharePoint. For Developers: Investigate and address the compatibility issues between SharePoint's ServiceWorkers and Firefox to prevent download interruptions.