TwinCAT Tree Item Not Found

What does TSM_E_ITEMNOTFOUND mean?

The specified tree item could not be found using the provided identifier (0x98510001). This can occur with LookupTreeItem() (absolute path name), LookupTreeItemById() (itemType/itemId combination), LookupChild() (relative path name), CreateChild() (bstrBefore item not found), DeleteChild() (bstrName item not found), ExportChild() (bstrName item not found), or ChangeChildSubType() (bstrChild item not found).

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Ensure the TwinCAT configuration is correctly loaded and matches the expected structure.

2. 4

   Check for case sensitivity or leading/trailing spaces in item names if applicable.