Run Sage as Administrator

sorry we tried that one too

Make sure your PUs are up to date

here is our PU update to 2020

Reinstall workstation setup.

the error is also on the sage server 

Run workstation setup on the server

still the same

First , that error has nothing to do with restart maintenance.  Second, reboot everything, something screwy is wrong, this is not a normal problem.

i think it is because its showing below error when login

No.  The restart message has NOTHING to do with the other error.

so what is the issue then that is what i want to know 

Your Sage installation is incorrect.  Do a repair and reinstall the PU.  

it was working fine after we did the PU  and suddenly after two month this error started to show 

Then your Windows environment must have changed, or some other program is interfering.  Reboot and reinstall.