i have pcs7 v9.1 installed on my windows entreprise LTSC 2019 it was working perfectly but after updates of windows (updates for net framework) i have problems with Plc sim ( is not responding ) and As/os engineering also not working when i compile object shows multiples errors and with graphics designer in step7 symbol server 

i have uninstall and instal plc sim and did try to repair it same problem 

i have uninstall Pcs7 and install it back same problem 

and also i have problems with simit sp demo is not working 

any solution please ?

tank you

Hi,

Did you follow this FAQ, with tested Windows Updates?

Which Microsoft Updates have been tested for compatibility with SIMATIC PCS 7?

Are you able to revert the installed Windows update?

How to uninstall a Windows update - Microsoft Support

With best regards,
Cedric