While trying to delete the pattern extension, you may see the below error and fails to delete that extension.

""

Failed to remove item: [object] [Object]

""

Cause #1. The related extension reference or its dependent references (referenced Libraries) might have deleted. OR

Cause #2. The extension might be in different scope.

Issue #1:

• Goto sa_pattern_extension list and look for that name and see if that extension exists in that table by clicking on the record.
• If the above is correct then look for the library references used in that extension and make sure those references exists.
• If any of these records are missing then check your "Deleted Records" module and if you find them restore. Else try to import from other instances using the Export to XML and Import XML.

Issue #2:

• Goto sa_pattern_extension list and check the application, domain by checking the message on the top or by using Show XML UI action.
• Make sure you are in that application and domain and then try to delete the extension.