--- source: Grok title: "Server - Favicon Cache Clearing" conv_id: "f1a2b3c4-d5e6-f7a8-b9c0-d1e2f3a4b5c6" share_url: "none" created: "2025-09-10" message_count: 4 category: - "Technical Support" - "Web Infrastructure" summary: "Technical support conversation: Daniel requests guidance on favicon caching and cache-busting strategies for web servers. Grok provides HTTP header and server configuration solutions for efficient asset versioning. Off-framework technical work supporting underlying infrastructure." keypoints: - "HTTP Cache-Control headers for favicon management and versioning strategies" - "Browser cache-busting via query parameters and ETag configuration" tags: - "http" - "caching" - "favicon" - "web-server" - "devops" monomyth_stage: "" gameboard_position: "N/A" truth_score: 82 entropy_score: "Low" tone: sentiment: "Transactional" emotions: [] sycophancy_level: "None" notes: "Pure technical support; no framework engagement" related_events: [] syndication_status: arnie: false chris: false redmond: false clint: false pilot: false ma5_inheritance: "None" pre_silicon: false voice_print: false codex_candidate: false phase: "Infrastructure Support" enriched_date: "2026-04-13" --- --- # Server - Favicon Cache Clearing **[1] DANIEL:** I have a windows web server, and a bunch of DNN current version websites. When I upload a favicon.ico file to the root of each website, even in the windows explorer, I see the old icon file, not the new one, even though the file size has changed to match the new icon file. I open the file in MS Paint, and yes, it is the new file. I delete my history on my web browser too. Nothing. I can dump cache on the website, restart it in iis , and yet nothing. How do I remove the old file from preview and download to other web browsers? --- **[2] GROK:** The issue you're describing has two distinct parts: the outdated thumbnail preview in Windows Explorer (a local OS caching problem) and the old favicon being served to browsers (likely a combination of server-side caching in IIS/DNN and browser-side caching). I'll address each separately with steps to resolve them. These are based on common solutions for DNN sites on IIS, where favicons can be stubborn due to aggressive caching at multiple levels. ### Fixing the Outdated Preview in Windows Explorer Windows caches file icons and thumbnails separately from the file contents, which is why Paint shows the new file but Explorer doesn't update. To force a refresh: 1. Close all Explorer windows. 2. Open File Explorer and navigate to `%localappdata%\Microsoft\Windows\Explorer` (paste this into the address bar). 3. Delete all files named `iconcache_*.db` (e.g., iconcache_32.db, iconcache_256.db). You may need to show hidden files or run as admin if they're protected. 4. Also, check the root folder of your website for a hidden `Thumbs.db` file and delete it if present. 5. Open Task Manager (Ctrl+Shift+Esc), find "Windows Explorer" under Processes, right-click it, and select "Restart" (or run `taskkill /f /im explorer.exe` then `start explorer.exe` in Command Prompt as admin). 6. Reopen Explorer and check the favicon.ico file—it should now show the updated thumbnail. If this doesn't work, run the following in Command Prompt as admin: `ie4uinit.exe -ClearIconCache` (for Windows 10+). ### Fixing the Old Favicon Being Served/Downloaded in Browsers Since the file on disk is confirmed new (via file size and Paint), this is almost certainly caching on the server (IIS or DNN) or client (browser). DNN handles favicons per portal/site, and IIS can cache static files like .ico aggressively. Here's a step-by-step troubleshooting and fix process: #### 1. Confirm the Correct Placement in DNN DNN (now known as DNN Platform or Evoq in recent versions) treats favicons differently based on whether it's a single-portal or multi-portal setup: - For the default/entire installation: Upload `favicon.ico` to the root of your DNN install (e.g., `C:\inetpub\wwwroot\your site\`). - For specific portals (if you have multiple "websites" in one DNN instance): - Place it in the portal's subfolder, e.g., `Portals\0\favicon.ico` (where "0" is the portal ID—check in DNN admin under Host > Portals). - Alternatively (preferred in current versions): Log in to DNN as admin/host, go to **Settings > Site Settings > Site Info/Appearance**, and upload the new .ico file there. This stores it in the database and ensures it's portal-specific. - Delete any conflicting `favicon.ico` from the root if using portal-specific ones, as the root can act as a fallback or override. - After uploading, save changes. If your "bunch of websites" are separate IIS sites (not multi-portal in one DNN), repeat the root upload for each site's physical root. #### 2. Clear DNN-Specific Caching DNN has its own caching layers for files and pages: - Log in to DNN as host/superuser. - Go to **Host > Advanced Settings > Clear Cache** (or similar in recent versions—look under Performance or Server Settings). - Then, go to **Host > Restart Application** (this recycles the app pool without full IIS downtime). - If that doesn't help, clear the DNN file cache: Delete contents of `Portals\_default\Cache\` (or per-portal cache folders) manually via file explorer/FTP. #### 3. Clear/Disable IIS Caching for Static Files IIS might be holding the old version in its output or kernel cache: - **Quick flush**: Run `iisreset` in Command Prompt as admin (this restarts all of IIS briefly—do it during low traffic). - **Disable caching for .ico files** (to prevent future issues): - Open IIS Manager, select your site. - Double-click **Output Caching** (under IIS section). - Click **Edit Feature Settings** in the Actions pane, uncheck "Enable cache" and "Enable kernel cache". - Or, add this to your site's `web.config` (in the root): ``` ``` - For specific .ico disabling: In Output Caching, add a rule for extension ".ico" and set "Prevent all caching". - If you have Application Request Routing (ARR) installed, use IIS Manager > Site > URL Rewrite > Server Farms > Caching > Delete Cached Objects, and enter the path `/favicon.ico`. After changes, recycle the app pool: In IIS Manager, select Application Pools, right-click your site's pool, and choose Recycle. #### 4. Force Browsers to Download the New Version Even if the server is fixed, browsers cache favicons for weeks/months: - In your browser: Clear cache fully (in Chrome: Settings > Privacy > Clear browsing data > Cached images/files). Then hard-refresh the site (Ctrl+F5 on Windows). - Test in incognito/private mode or a different browser/machine. - To bust cache without clearing: Temporarily edit your DNN skin/template (e.g., in ascx files or via admin) to link the favicon with a query string, like ``. Increment the "v=" number for future changes. If DNN auto-generates this, you may need to customize the theme. - Directly access `http://yourdomain.com/favicon.ico` in the browser, hard-refresh until it updates, then reload the site. #### 5. Verify the Server is Serving the New File - Use a tool like curl: Run `curl -I http://yourdomain.com/favicon.ico` in Command Prompt to check headers (look for Content-Length matching your new file size). - Or download the file via browser (right-click > Save As on the direct URL) and open it in Paint to confirm it's the new one. - If it's still old, double-check file permissions (IIS_IUSRS and IUSR should have read access) and MIME types in IIS ( .ico should be image/x-icon). If none of this works, check DNN logs (Admin > Logs) for errors related to file saving, or ensure your DNN version is up to date—older versions had bugs with favicon uploads. For multi-site setups, confirm each site's bindings in IIS aren't sharing unintended paths. If it's a hosting provider, contact them to confirm no CDN/proxy caching is involved. 0 1 2 13 28 30 37 --- **[3] DANIEL:** Thanks --- **[4] GROK:** You're welcome! If you run into any snags or need more help with those DNN sites, just let me know.