Duplicate Content Items appearing during Sitecore Upgrade to 10.2

Question

We are in process of upgrading Sitecore 8.2 to 10.2 Have ran the upgrade scripts on the existing databases as mentioned in the Upgrade guide. In the Sitecore Content Editor, its displaying duplicate items throughout the tree structure. Duplicate items has same ID.

Tip: Sitecore 8.2 solution was using TDS but we are not using it for 10.

Please check the screenshot.

Can someone please help?

Answer 1

I hope you have also performed the Clean up the content databases. Database clean-up is a one-time operation. If not then please follow the below steps:

The Sitecore.UpdateApp is a standalone console tool. To clean up the content databases:

1. On the Sitecore Launchpad, open the Control Panel, in the Database section, click Clean up databases, select all the databases, and then click Clean.
2. Locate the Sitecore.UpdateApp 1.2.0 for Sitecore X.X.X rev XXXXXX.zip file that you downloaded earlier and extract its contents to a folder, for example, C:\Sitecore.UpdateApp.
3. Copy the license file to the Data folder of the tool, for example, C:\Sitecore.UpdateApp\Data\license.xml.
4. In the C:\Sitecore.UpdateApp\App_Config\ConnectionStrings.config file, update the connections to your databases. If you do not have a security database, use the connection to the core database.
5. Add the upgrade resources from every module and connector to the UpdateApp Tool files.

You can download the upgrade packages for the different versions of the Sitecore modules from the Sitecore downloads site and you can find links to the compatible modules on the Sitecore XP downloads page.

1. Download the items as resources zip file for the module version that is installed on your solution. If the module or the connector has several versions, there are separate folders for each version.
2. Unpack the zip file into a local folder, for example, c:\ModulesUpgradeResources\[Module Name].
3. Copy all the subfolders and files from the Data folder, for example, from c:\ModulesUpgradeResources\[Module Name]\X.X.X\Data.
4. Paste all the subfolders and files into the UpdateApp Data folder, for example, C:\Sitecore.UpdateApp\Data.
5. Repeat this procedure for every module and connector.

6. Open a Command Prompt in the tool folder and run: Sitecore.UpdateApp.exe clean The number of items that are removed from each database is listed in the Command Prompt window. Detailed information about any modified items that are skipped is written to the log files in the tool folder – \Data\logs.
7. To clear the caches, open the <instance_url>\sitecore\admin\cache.aspx page, click Refresh, and then click Clear.

Answer 2

Items can't exist with the same IDs in the master DB. Therefore the only two scenarios that I can think of that would produce duplicate items are:

1. somehow the introduction of second data source (i.e. file based which comes in SC10). But I have had time where item exists in both file and DB and this hasn't produced duplicate item.

2. a deserialisation issue where by a second entry is added to the index rather than replacing the old one. This is imo the most likely scenario, which should be solved by a simple reindex of the master index.

Please try reindexing master index and let me know if this resolves the problem.