Keep getting message Unhandled exception has occured in a component in your application.

[S.W.Eng]

Hi all I  am running Autocad LT 2025 on  Windows 10, I seem to be having this problem when I hit the CUI in quick properties I will get a pop up saying,

"Unhandled exception has occured in a component in your application.  if you click continue, the application will ignore this error and attempt to continue.

Could not load file or assembly "System. Text.Encoding.CodePages,Version=8.0.0.0, Culture=neutral, publickey Token=b03f5f7f11d50a3a". The system cannot fine the file specified.

If I hit continue, it does take me to the Customize user interface, I can make changes , then hit apply, hit ok to close and the the same message pops up again, hit continue to close and the changes made seem to stick.

Its just a pain to keep getting this message, anyone have any ideas to fix this?

This happens on a new sheet, the file has no bearing on it happening or not.

[S.W.Eng]

Here is a screenshot of the error.

[pendean]

@S.W.Eng Is this a problem that just appeared today?

Or is this a new LT2025 installation?

Or...?

I will assume you've done that very basic restart-of-PC solution already: an LT2025 reset may be in order at some point too

https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/How-to-reset-AutoC...

[paullimapa · Accepted solution]

have you installed LT 2025.1.1 update?

[S.W.Eng]

I don't know when it started but I noticed the issue about 2 weeks ago, just never looked into it until the day I posted this since i couldn't find any info on it. I have done a computer restart and a reset settings to default , 

[S.W.Eng]

I have not, I didnt know there was a new update, will try it now.

[S.W.Eng]

updating fixed my problem, Thank you.

[paullimapa]

Glad that worked out for you…cheers!!!

[petervoegeli]

I have this problem with Mechanical 2025 sp0 - sp1.2.

2025-04-09 16:12:34.5465 ERROR Fatal Autocad Errror System.IO.FileLoadException: Could not load file or assembly 'System.Text.Encoding.CodePages, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. Could not find or load a specific file. (0x80131621)
File name: 'System.Text.Encoding.CodePages, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
---> System.IO.FileLoadException: Could not load file or assembly 'System.Text.Encoding.CodePages, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.

A reset did not help

It was working, but stopped now.

Regards

[paullimapa]

Have you tried resetting?

How to reset AutoCAD to defaults

May get better feedback by posting over here:

https://forums.autodesk.com/t5/autocad-mechanical-forum/bd-p/39

[petervoegeli]

Resetting and/or installing SP 1.1 or SP 1.2 did not help.

I needed to downgrade to version 8 of the *.dll, now it is working.

Strange that it was working correctly....

Regrads Peter