I have a forming tool that I use frequently in our sheet metal parts. I normally check Link to form tool option in its property sheet while adding it.
Sometimes (though not always) I see a question mark in front of this forming tool in feature tree.
That obviously shows some external references are missing. But when I right click it and select list external Refs.... nothing is missing.
The attached assembly has a virtual part (01) that shows this problem.
The form tool is attached as well.
How can I fix these missing links or prevent my assemblies showing these question marks in feature tree.
Windows 10 with latest updates
Solidworks 2018 Sp0.1
Forming tool is placed in a local folder (D:\SolidWorks\Docs\My Design Library\Forming Tools)
Any kind of help is appreciated.