Hi Francois,

You can browse the following thread for the same issue as yours. I hope this can solve your problem.

Best Regards,

Julia

I did see that and applied the suggested remedy, but it does not solve it.

However, it definitely has something to do with the "system.xxxxxxx " references, since these started to appear as references both in my application's BIN directory as well as from the GAC. 

I don't know how exactly I solved the issue, but I basically deleted all references to system.xxxx and IS.xxxxx from my application, as well as physically deleting them from my BIN folder.  I then also stopped IIS, dleted my temporary asp.net files and restarted IIS.  Lastly I manually added all the IS controls I use to a new page in order for them to be added back to my BIN folder and the necessary references to be created.

Seems to work now, although this cost me sooooo much valuable time for something that should have been a painless upgrade.

Francois

Hi Francois,

Glad to hear your problem solved . Since the problem's condition happened to be unpredictable, your solution will become a precious information for all of us. Thank you very much for sharing it with us. And please let us know if you need another help.

Best Regards,

Julia

Hello, just add the DLL as referenicaSystem.Runtime.Serialization.dll  Saludos

Oscar