Is it possible to delete Arrowhead types?

[gopinath.rajendran]

var arrowHeads = new FilteredElementCollector(doc).WhereElementIsElementType().Cast<ElementType>().Where(t => t.FamilyName == "Arrowhead").ToList();

using (Transaction trans = new Transaction(doc, "Remove Arrowhead"))
{
trans.Start();

foreach (var arrowHead in arrowHeads)
{
doc.Delete(arrowHead.Id);
}

trans.Commit();
}

Throws an Autodesk.Revit.Exceptions.InternalException: 'An internal error has occurred,' and then Revit crashed

[jeremy_tammik]

Maybe the type is in use? Can you share a complete minimal reproducible case for us and the development team to take a closer look?

• https://thebuildingcoder.typepad.com/blog/about-the-author.html#1b

Thank you.

P.S. Your code will be more readable if you use the insert code button marked </> to add it to your post.

[Mohamed_Arshad]

Hi @gopinath.rajendran 

     You can't able to delete the System Types, we can able to purge the system types. Kindly check the below link for additional reference.

Reference Image

Reference Links

https://forums.autodesk.com/t5/revit-api-forum/purge-unused-via-the-api/td-p/6431564 

https://thebuildingcoder.typepad.com/blog/2017/11/purge-and-detecting-an-empty-view.html

https://thebuildingcoder.typepad.com/blog/2022/03/purge-unused-and-the-autodesk-camel.html 

Hope this will Helps 🙂 

[gopinath.rajendran]

After the exception mentioned above, if I try to commit the transaction, the following window appears

I couldn't replicate the crash in a separate piece of code. Maybe resolving this error will fix the crashing issue. After encountering the first error window, Revit always crashes when using the plugin.

Here complete code:

var doc = ActiveUIDocument.Document;
var arrowHeads = new FilteredElementCollector(doc).WhereElementIsElementType().Cast<ElementType>().Where(t => t.FamilyName == "Arrowhead").ToList();

using (Transaction trans = new Transaction(doc, "Remove Arrowhead"))
{
trans.Start();

foreach (var arrowHead in arrowHeads)
{
try
{
doc.Delete(arrowHead.Id);

}
catch (System.Exception ex)
{
}
}

trans.Commit();
}

This error window can be replicated using the rac_basic_sample_project.rvt sample model in Revit.

it happens on Revit 2023, Revit 2024 and Revit 2025.

[gopinath.rajendran]

@Mohamed_ArshadThanks for your input. It's not about deleting all the elements. I need to know how to prevent Revit from crashing when an element is not deletable.

[naveen.kumar.t]

Hi @gopinath.rajendran ,

You can determine whether the Arrowhead type is deletable or not by using the CanBeDeleted property.
This will help prevent Revit from crashing.

https://www.revitapidocs.com/2015/5efe8253-d555-00c2-8db6-9114e328fcc7.htm 

[gopinath.rajendran]

@naveen.kumar.t  I tried this before, and it is true for all elements.

[Mohamed_Arshad]

HI @naveen.kumar.t  @gopinath.rajendran 

     @naveen.kumar.t  I checked the mentioned property but it true for Arrow Head, My suggestion is to try use IFailurePreProcessor to handle Revit based errors. If we got any serious errors we can skip the process without crashing Revit.

Hope this will Helps 🙂

[naveen.kumar.t]

Hi,

I’ve escalated the issue to the Revit Engineering team, and I’ll get back to you as soon as I hear from them

[naveen.kumar.t]

Hi @gopinath.rajendran ,

I have tested deleting all arrowhead types and was able to remove all except "Arrow Open 90 Degree 1.25mm".

Each time I attempt to delete this specific arrowhead type, I encounter an exception/crash.
The issue persists regardless of whether I try to delete this arrowhead type first or last.

Could you please verify if the same arrowhead type is causing the issue on your end?

[gopinath.rajendran]

Yes. It is

[naveen.kumar.t]

The Arrow Open 90 Degree 1.25mm arrowhead type is being used by a component.

Upon reviewing the journal file, I discovered that this particular arrowhead type is internally utilized by StairsPathType StairsPathType::setArrowheadTypeId.

This explains why Revit throws an exception when attempting to delete it.