SSEO - SuperSync Add‑In Appears Blank in Outlook

When the SuperSync add-in opens as a blank or empty window, the most common cause is corrupted cached data. Outlook add-ins rely on cached files to load quickly, and when those files become outdated or damaged, the add-in may fail to render. Before you begin, save any work you have open, because clearing cache can remove temporary data stored by Outlook or your browser. Clearing cache can also remove saved logins from websites, which may require you to sign in again afterward.


Why Cache Can Become Corrupted

Cached data can become invalid or damaged for several reasons:

  • Updates to Outlook or the browser engine that conflict with older cached files.

  • Network interruptions while the add-in is loading resources.

  • Security software blocking or altering cached content.

  • Add-in updates that require new files while the system continues using older cached versions.

  • Storage issues on the device that prevent cache files from writing correctly.

Any of these can cause the SuperSync add-in to appear blank.


Perform Basic Checks

Before clearing cache, confirm the following:

  • Outlook is fully updated.

  • Your internet connection is stable.

  • No firewall or security tool is blocking add-ins.

  • The issue occurs consistently, not just once.

If the add-in still appears blank, continue with the cache clearing steps.


Clearing Cache in Outlook Web App (OWA)

If you are using Outlook on the web, also known as OWA, clearing your browser cache may resolve the issue. OWA relies entirely on your browser’s cached files to load add-ins.

Clear Cache in Microsoft Edge

  1. Open Edge.

  2. Select Settings and more (three dots) and choose Settings.

  3. Select Privacy, search, and services.

  4. Under Clear browsing data, select Choose what to clear.

  5. Select:

    • Cached images and files

    • Cookies and other site data (optional but helpful)

  6. Select Clear now.

  7. Sign back into OWA and test the add-in.

Clear Cache in Google Chrome

  1. Open Chrome.

  2. Select Settings and go to Privacy and security.

  3. Select Clear browsing data.

  4. Select:

    • Cached images and files

    • Cookies and other site data

  5. Select Clear data.

  6. Sign back into OWA and test the add-in.


Clearing Cache in Desktop Outlook

These steps apply to the desktop version of Outlook. For reference, Microsoft provides official instructions on clearing the Outlook add-in cache: https://learn.microsoft.com/en-us/office/dev/add-ins/testing/clear-cache#manually-clear-the-cache-in-outlook

Because these steps involve deleting local application data, you may need assistance from your IT department, especially if your organization manages Outlook profiles, system policies, or device permissions.

Classic Outlook for Windows

  1. Close Outlook and any other Office products completely.

  2. Open File Explorer.

  3. Go to the following folder and delete all files inside it:

    Code


    %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\

  4. SuperSync Email also uses the unified manifest, we also need to delete:

    Code


    %userprofile%\AppData\Local\Microsoft\Outlook\HubAppFileCache

  5. Reopen Outlook and test the SuperSync add-in.

New Outlook for Windows

  1. Close Outlook.

  2. Open Command Prompt.

  3. Run:

    Code


    olk.exe --devtools

  4. Outlook will open along with Microsoft Edge DevTools.

  5. Open the Network tab in DevTools.

  6. Right-click anywhere in the request list and select Clear browser cache.

  7. Close Outlook and reopen it normally.


Clearing Office Web Cache (If Needed)

If the add-in still appears blank, you can clear the Office web cache through DevTools.

  1. Open Outlook and launch the SuperSync add-in.

  2. Open Microsoft Edge DevTools.

  3. Select the Local tab and locate the add-in.

  4. Open the debugger window that appears.

  5. On the Network tab, select Clear cache.

This forces Outlook to reload all add-in resources.


Restart and Test

After clearing caches:

  • Restart Outlook.

  • Open the SuperSync add-in again.

  • Confirm whether the task pane loads correctly.

If the add-in still appears blank, the issue may be related to:

  • A corrupted Outlook profile

  • A disabled service or policy

  • Add-in manifest or deployment issues

  • Network restrictions are blocking the add-in domain

Your IT department may need to investigate these system-level issues.



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