Error 1001 During Installation or Update

Symptoms

When you attempt to install or update Office Timeline, you receive the following error:

“Error 1001. An exception occurred while uninstalling.”

Overview

This issue typically occurs when a previous version of Office Timeline was not removed correctly.

In many cases, this happens when upgrading from an older VSTO-based version (installed per machine) to the current version (installed per user). The installer may fail while attempting to remove the older version.

Solution

To resolve this issue, fully remove the previous installation and then install the latest version.

1. Uninstall Office Timeline
   • Go to Settings → Apps → Apps & features
   • Locate Office Timeline and click Uninstall

2. If uninstall fails
   Use the Microsoft uninstall troubleshooter to remove the application completely.

   Follow the steps in the Uninstall Office Timeline article.

3. Install the latest version
   Download and install the latest build from:
   https://www.officetimeline.com/updates

Additional Notes

• This issue is most common when upgrading from older VSTO-based versions
• The current version installs per user and does not require administrator privileges for most installations
• If the issue persists, your IT team may need to assist with removing the previous installation