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ErrorLib — Industrial Fault Code Library

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TSM_E_ITEMNOTFOUND

TwinCAT Tree Item Not Found

Beckhoff · TwinCAT 2 Automation Interface

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).

Common Causes

  • The specified TwinCAT variable or object identifier does not exist.
  • A reference to a non-existent tag in the PLC project.
  • An attempt to access a memory address that is not mapped.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the exact path name (absolute or relative), itemType, itemld, or bstrName/bstrBefore/bstrChild argument for typos or incorrect hierarchy.

  2. 2

    Use the TwinCAT System Manager to visually confirm the existence and exact properties (name, type, ID, path) of the target tree item.

  3. 3

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

  4. 4

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

Browse all codes in this manual (12)
Verified technical data. Last updated: April 2026

Related Faults

E_ACCESSDENIEDAccess DeniedE_FAILGeneral Function FailureE_INVALIDARGInvalid Argument Provided
Source: Beckhoff TwinCAT 2 Automation Interface
Open Manual (Page 34)Search more codes in this manual