Worksession - How to remove "File not found"?

OK, so I have (had) a file which is no longer found on disk, but there is no option in Worksession manager to remove a file which has been removed from disk. Such an option should be added.

So, of course I try a workaround by creating a fake file with this name and filepath, but then Rhino cunningly replies like so:

Hm. Now what? How do I clean out that missing file reference?

// Rolf

Hi Rolf - just highlight it in the list and poke ‘Detach’… does that do it?


No, all buttons are dead, except for Attach… :upside_down_face:

But what if you highlight that item in the list?




Yes, I tried that, but all buttons are dead except for Attach (sorry that my first screenshot didn’t show that I meant that the buttons were dead while selecting the missing file ref):

Like so. No option to detach:

// Rolf

Ok, I see - I tried to reproduce the situation and I was able to select and detach the file… let me have another go…

I get this on opening a rws file for which one attached file has been deleted:

Rhino 6  Open Reference File Error
Unable to read the reference file named


When Rhino is finished reading the work session file, you may 
use the "Worksession" command to edit the list of reference files.

then I see this, in Worksession:


So I am doing something different but I do not see what yet.


Try rename “SyncViews.3dm” and open Worksession. Then close WS and remove the file and try open WS again. Are you then out of option to detach?

BLOCK (Worksession)
I have another problem with Worksessions. if I open a file (part of WS) and start inserting a block, but then aborts the insertion before confirming the insertion, then I still see the Block’s layers show up in the file (not expected) but no block in the Block manager (as expected). And if I try to delete those layers it refuses due to a Block definition on the layers (which are not there, at least not visible in the block manager.

Solution: Close Worksession altogether and open the individual file, then it allows you to remove the aborted block insertion layers.

Perhaps this post should be split, but it seems to be a problem with Worksessions messing up files/references in runtime.

// Rolf

Hi Rolf - hmmm- so far it all works. …


Can it be related to me opening old R5 files and then saving them to R6 and… somehow Rhino gets messed up?
(But I did introduce Worksession only today, not in 2016 when the individual files were first created).

Hi Rolf - can you repeat the setup from scratch? If so, please give me the blow-by-blow, there is something I am missing…


Yup, I finally was able to reproduce:

  1. make Folder A\Model A.3dm
  2. make Folder B\Model B.3dm
  3. Set Folder A\Model A.3dm as the active model
  4. Save Worksession i Folder A and close it.
  5. Rename or delete Model A.3dm
  6. Open Worksession
  7. –> Detach not available for the missing file.


So #3 makes all the difference (If any other Model file is active when deleting Model A.3dm, then the error does not occur, so I also struggled with reproducing this… :slight_smile: )

// Rolf

Hi Rolf - thanks, I’ll test this.


Hi Pascal, has this been looked at lately? I also have the same issue.


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Hi @pascal ,

Same issue here, no way to detach the missing file:

First few minutes working on my Worksession to experiment with it before integrating it into the workflows and this big issue pops up: Work Session Attach Failed.


The file is already attached to work session.

I make the wrong assumption

I will not use “set active model” until this bug is fixed because it destroy my first worksession.

Always buy design bug

  • In Layers, right-click and attach a model
  • Select that worksession reference and set it as Active Model
  • In the 3D select the model and delete it
  • Open worksession Manager
  • Try to delete the reference

The button “Detach” is hidden or inactive. If I try to attach that file a warning message pops up.
Expected: The button “Detach” is active and it is possible to take out the reference and reimport the reference file.

Hello - if I follow, you are trying to detach the active model…?


I try to make a video asap.

PS: Yes, I was trying to detach and attach but a warning “Work Session Attach Failed” pops up

Hello - ok - well, there the active model is not an attached model, so it cannot be detached. I’m not clear on what it is you are trying to accomplish.


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I was trying to be confident and looking at what the worksession was capable of.

Let say
I try to re-attach the file.


Bug report: RH-57515