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BindingRedirect Madness: Fixing Broken Assemblies After a Sitefinity Upgrade

Upgrading Sitefinity can trigger a flood of runtime errors due to outdated binding redirects and broken assembly references. In this post, we break down why these issues occur and share a step-by-step guide to cleaning up your config, fixing feeds, and restoring stability.

Daniel Plomp

14 Oct 2025 — 2 min read

Upgrading a Sitefinity project can sometimes feel like walking through a minefield of assembly errors. You pull in the latest Sitefinity NuGet packages, run your site, and suddenly you’re greeted with dreaded runtime exceptions like:

“Could not load file or assembly 'Telerik.Sitefinity.Frontend.Media, Version=14.4.8144.0...'”

This “binding redirect madness” is a common frustration. In this post, we’ll explore why these issues arise, how to fix them step-by-step, and offer config cleanup tips to future-proof your setup.

Why Binding Redirect Errors Happen

Version mismatches: New Sitefinity versions update DLLs. Old references in configs or custom code trigger conflicts.
Leftover redirects: Web.config may still point to outdated versions.
Deprecated/renamed assemblies: Some DLLs get replaced or dropped entirely in newer versions.
Incomplete NuGet updates: Bad feeds or broken restores can silently leave old DLLs in your solution.

Step-by-Step Fix Guide

1. Remove Old DLLs

Manually clean your /bin folder and ensure all Telerik.Sitefinity.* assemblies reflect the current version.

2. Update Web.config Redirects

Adjust your <bindingRedirect> entries:

<bindingRedirect oldVersion="0.0.0.0-15.3.7300.0" newVersion="15.3.7300.0" />

Only include redirects that are actually needed. Remove duplicates or legacy entries.

3. Clean Up Conflicts

Remove redirect entries for renamed or removed assemblies
Strip out auto-generated system assembly redirects (like System.Linq) unless required
Rebuild your project and check build output for old versions

4. Fix Your NuGet Setup

Disable broken or expired custom feeds
Reinstall Sitefinity packages using Update-Package -reinstall
Verify that all projects use consistent versions

5. Use Logging Tools

Check ~/App_Data/Sitefinity/Logs/UpgradeTrace.log for upgrade issues
Enable Fusion Log Viewer (Fuslogvw) to trace binding failures
Increase MSBuild verbosity to track lingering references

Config Cleanup Tips

Remove legacy modules or unused config sections
Consolidate multiple redirects into broad ranges
Disable auto-binding generation if it introduces noise
Review NuGet packages and trim unused dependencies

Upgrading Sitefinity doesn't have to be painful. Most binding redirect chaos stems from mismatched versions or lingering config debris. Clean your assemblies, verify your NuGet feeds, and simplify your redirects — and you'll be back on track.