“Can't find symbol for specified part” Error in Plant 3D 2026 – Custom Block-Based

[SoftFit_Iain]

Hi all,

I’m running into a persistent issue in AutoCAD Plant 3D 2026 when working with custom block-based components.

I've created a number of custom components using block-based geometry and added them to a spec using Spec Editor 2026. The symbols are located in a centralised folder, and PLANTCONTENTFOLDER is correctly set across the environment.

The setup works fine in Spec Editor — parts appear as expected and the specs save without issue and look to refer back to the same catalog. However, when I try to add these parts in Plant 3D 2024, I get the following error:

“Can't find symbol for specified part.”

Important context:

• The spec and catalogue are not new — I'm copying parts between specs within the same catalogue.

• The symbol DWG files are present in the shared content folder.

• PLANTCONTENTFOLDER is pointed to the correct shared location and all users are accessing the same path.

• The spec part was copied from another and the PartFamilyId differs between the source and target specs, however the CatalogPartFamilyId is consistent.

To troubleshoot, I’ve initiated BEDIT in the DWG symbol file and done a Save As using the new PartFamilyId as the GUID referenced in the spec I have pasted in to — however, the issue persists.

I’m trying to determine:

1. Whether there's an internal reference or path that needs refreshed or reloaded.

2. Whether the PartFamilyId mismatch is breaking the link despite the block being correctly named and stored.

3. Any known bugs or fixes related to this error in 2026.

Would appreciate any insights or troubleshooting steps others have found useful. Screenshots below for ref.

Thanks,
Iain

PartFamilyId of copied part

PartFamilyId of pasted part

[h_eger]

@SoftFit_Iain ,

Do you work with the 2026 content folder in P3D 2026 and the 2024 content folder in P3D 2024?
There is a folder ‘CatalogSupportFolders’ in your 2026 content folder if you copy it into the 2024 content folder your problem should be solved.

[SoftFit_Iain]

Hi @h_eger 

I’m afraid that doesn’t appear to be the case. We use a client-specific content folder named "*Client*-P3D-Lib", and the catalogues within it can be accessed from both 2024 and 2026. The content location has been updated across all versions we use via registry edits, so all updates should point to the same folder regardless of version.

I’ve also searched for the block GUID as shown in snips in the standard 2026 folder but haven’t found any matches.

I was able to add the parts directly from the catalogue, which worked as expected - this might indicate a potential issue in the logic when copying block parts from one spec to another?

Thanks for your assistance again!