Users cannot create issues due to Issue Matrix error “Duplicate plugin found” / “model/1.9" not found

Summary:
This article provides troubleshooting steps for resolving errors related to missing packages and response timeouts in the Issue Matrix for Jira app on Jira Data Center. The issue typically occurs after downgrading the app or when duplicate plugin files are present, resulting in errors such as Package with uri 'http://www.botronsoft.com/issuematrix/model/1.9' not found and users being unable to create issues.

Affected products

• App: Issue Matrix for Jira (Data Center)

• Jira platform: Data Center (10.3.7)

• App versions involved: 6.0.0‑jira9‑10, 6.1.1‑jira9‑10, 6.1.2‑jira9‑10

The issue typically appears after:

• Several install / uninstall / upgrade / downgrade operations of Issue Matrix, or

• A downgrade from a newer Issue Matrix version (for example 6.1.1) to an older one (for example 6.0.0).

Symptoms

Users may report:

• They cannot create issues – the Create dialog spins or times out.

• Issue pages with Issue Matrix custom fields time out or load very slowly.

In the Jira logs (atlassian-jira.log) you may see:

and/or:

Cause

There are two related causes:

1. Duplicate plugin files

   • Multiple Issue Matrix JAR files exist under:

     $JIRA_HOME/plugins/installed-plugins

   • Jira detects more than one version of the same app and logs:

     Duplicate plugin found (installed version is newer)

2. Downgrade to an incompatible version

• A newer version of Issue Matrix (for example 6.1.1 or 6.1.2) upgrades its internal configuration to a newer model (for example model 1.9).

• If you then downgrade to an older version (for example 6.0.0) that does not know this model, it cannot read that configuration and logs the “model/1.9 not found” error.

The combination of these two issues can cause timeouts on Create Issue and when loading issues that use Issue Matrix fields.

Resolution

These steps require a maintenance window and filesystem access on all Jira nodes.

1. Check for duplicate Issue Matrix JARs

   1. On one Jira node, open the Jira Home directory.

      1. Go to:

         $JIRA_HOME/plugins/installed-plugins

      2. Look for files that contain issuematrix in their names, for example:

         • plugin.618556113595111841.issuematrix-6.0.0-jira9-10.jar
         • plugin.XXXXXXXXXXXXXXX.issuematrix-6.1.1-jira9-10.jar
         • plugin.XXXXXXXXXXXXXXX.issuematrix-6.1.2-jira9-10.jar

   2. If you see more than one issuematrix JAR, the duplicate plugin condition is confirmed.

      • For Jira Data Center, repeat this check on each node’s Jira Home.

2. Uninstall Issue Matrix from Jira

   1. In Jira, go to Administration → Manage apps.

   2. Find Issue Matrix for Jira.

   3. Click Uninstall.

3. Stop Jira

   1. For single‑node Jira: stop the Jira service.

   2. For Jira Data Center: stop Jira on all nodes in the cluster.

   Wait until all Jira processes are fully stopped.

4. Back up Jira

   1. Before changing files:

      • Ensure you have a database backup.

      • Back up the Jira Home directory (at least the plugins folder).

      • Optionally, back up the Jira installation directory.

5. Clean up the Issue Matrix and plugin cache

   1. Perform these steps on each node’s Jira Home:

      1. Remove Issue Matrix JARs

         • $JIRA_HOME/plugins/installed-plugins

      2. Delete all files that contain issuematrix, for example:

         • plugin.618556113595111841.issuematrix-6.0.0-jira9-10.jar plugin.XXXXXXXXXXXXXXX.issuematrix-6.1.1-jira9-10.jar plugin.XXXXXXXXXXXXXXX.issuematrix-6.1.2-jira9-10.jar

         • After this, there should be no issuematrix JARs left in installed-plugins.

   2. Clear Jira plugin cache directories

      1. Still inside Jira Home, remove the plugin cache folders (they will be re‑created automatically):

         • $JIRA_HOME/plugins/.bundled-plugins $JIRA_HOME/plugins/.osgi-plugins

      2. For Jira Data Center, also follow Atlassian’s official plugin cache clean‑up guide:

         • https://support.atlassian.com/jira/kb/how-to-clear-jira-data-center-server-plugin-cache/

6. Start Jira

   1. Start the first node, wait until it is healthy, then start the remaining nodes one by one.

   2. Wait until Jira is fully up and plugins have finished loading.

7. Install the latest version of Issue Matrix for Jira from the Atlassian Marketplace (recommended: 6.1.2-jira9-10 or newer).