Altium Designer Documentation

WorkspaceManager_Err-MultipleTopLevelDocumentsMultiple Top-Level Documents_AD

Created: August 7, 2017 | Updated: February 28, 2019
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Parent category: Violations Associated with Documents

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This violation occurs in hierarchical designs when two or more schematic sheets are at the top-level of the structure.


If compiler errors and warnings are enabled for display on the schematic (enabled on the Schematic - Compiler page of the Preferences dialog), an offending object will display a colored squiggle beneath it. Hovering over the object will display a pop-up hint that summarizes the violation. A notification is also displayed in the Messages panel in the following format:

Multiple top level documents: <SheetName> has been used


  • SheetName is the name of the schematic document currently being used as the top-level sheet.

Recommendation for Resolution

This issue typically arises due to the sheet symbol on the true top sheet not targeting the intended sub-sheet correctly. To resolve this issue, first determine which schematic sheet is the intended sub-sheet. Check to see if a sheet symbol has been placed for the intended sub-sheet on the top-level schematic:

  • If a sheet symbol does not exist, create it - either by manual placement or by using the Create Sheet Symbol From Sheet command (available from the main Design menu).
  • If the sheet symbol exists, ensure that it references the sub-sheet. Check the entry in the sheet symbol's File Name field in the Properties section on the General tab of the Properties panel (when the sheet symbol is selected in the workspace). The target document itself is specified in the Source section (on that same tab of the panel) with the source set to Local for a standard sheet symbol.

Upon recompiling, the hierarchy will be resolved and the error will disappear from the Messages panel.


  • Object hints will only appear provided the Enable Connectivity Insight option is enabled on the System - Design Insight page of the Preferences dialog. Use the controls associated with the Object Hints entry in the Connectivity Insight Options region of the page to determine the launch style for such hints (Mouse Hover and/or Alt+Double Click). 
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