Who is this article for?

Users who see this error when installing the client or when clicking on hyperlinks in documents.

No elevated permissions are required.

This article explains the causes of the error “You cannot start application [application name] from this location because it is already installed from a different location” and describes how to resolve it. There are two common scenarios that trigger this error, covered in the sections below.

Cause 1: Clicking a ClickOnce link from a different URL (most common)

This is the most frequent cause. It occurs when you click a ClickOnce link that points to the same application you already have installed, but the URL in the link differs from the URL used during the original installation.

How ClickOnce identifies installation sources

When ClickOnce installs an application, it records the exact URL used. If you later attempt to launch the application using a URL that differs in any way from the recorded one, ClickOnce treats it as an attempt to install the same package from a second, different location, and raises an error.

Common examples of URL mismatches that trigger this error:

• HTTP vs HTTPS: Installing from http://appserver.example.com/App/Client and then launching from https://appserver.example.com/App/Client
• Short hostname vs fully qualified domain name: Installing from https://appserver/App/Client and then launching from https://appserver.example.com/App/Client

This situation commonly arises when a hyperlink in a document, email, or other shared resource uses a different form of the server URL than the one originally used to install the application. Windows uses ClickOnce to resolve the hyperlink, and ClickOnce raises the error when the URLs do not match exactly.

The ClickOnce install log will contain a message similar to:

You cannot start application Pentana - PRD from location https://server.domain.com/PentanaUAT/Client/Vision.application?... it is already installed from location http://server.domain.com/PentanaPRD/Client/Vision.application.

Resolution

To resolve this error:

1. Use Add/Remove Programs (or Apps & features in Windows 10/11) to uninstall the application.
2. Open Microsoft Edge is recommended.
3. Navigate directly to the correct deployment URL — for example, https://server.domain.com/PentanaPRD/Client. Confirm the protocol (HTTP or HTTPS) and hostname format with your administrator if unsure.
4. Click the install button on the deployment page to reinstall the application from the correct URL.

Cause 2: Clicking a mismatching hyperlink in a document

This is actually a variation on cause 1, where the usual mechanism is:

• Some time ago, you installed the application from an address beginning http:
• You open a document containing a link to a record in Ideagen Internal Audit and click that link
• Microsoft Edge launches, and redirects you to the https: version of that URL
• This is seen as a different location, and fails with the error described above

As above, the solution is to:

• Remove the desktop client through Add/Remove Programs
• Reinstall, using the https: version of the deployment URL