Internal error of the multi thread sparse solver

[sre.thamilagaran]

Hi,

I am currently running a rather large RC structure. I receive the "internal error of the multi thread sparse solver" when performing the analysis.  I encountered this issue only after I added few additional loads and internal walls to the structure at the roof level (ventilation shaft). Earlier I had only type3 instability, but the model still completed the analysis. Now I am encountering instability type 1 as well.  The instability is shown in the wall meshes only which was fine before updating the model. I tried remeshing the wall but still it did not work. 

Thank you for your help.

[Stephane.kapetanovic]

hi @sre.thamilagaran 

The internal error and the type 1 instabilities are surely linked. If the nodes are free, your new panels may not be linked with the previous ones. can you share your model on the forum?

Best regards

https://knowledge.autodesk.com/support/robot-structural-analysis-professional/troubleshooting/caas/s...

https://forums.autodesk.com/t5/robot-structural-analysis-forum/vba-excel-macro-for-any-object-geomet...

https://apps.autodesk.com/RSA/en/Detail/Index?id=964813656627065816&appLang=en&os=Win64

[sre.thamilagaran]

Hi @Stephane.kapetanovic,

Thank you for the help. Due to the confidentiality of the project, I am unable to share the model. But I will check the if the new panels are properly connected.

Thanks,

[severin.wolff]

Hello,

at my model the issue "multi thread sparse solver" was also coming up. When I switched off the DSC-algorythm the application error No. 2809 came up.

What is the relation between them both?

Thank you!

[Stephane.kapetanovic]

hi @severin.wolff 

Error list

https://help.autodesk.com/view/RSAPRO/2025/ENU/?guid=GUID-8E8ED7A4-9A55-4F1F-8771-7E1A9CEF73B2

you probably have instabilities

https://forums.autodesk.com/t5/robot-structural-analysis-forum/poblem-with-modal-analysis-error-2809...

Best Regards