Is this the same PC that you used last week? (maybe a silly question, but you never know)
If not, you need to make sure that the Simulation was actually installed with WinCC. There is no extra license required, but it isn't installed by default.
Yes same PC that worked before.
I am trying to simulate in TIA portal. Worked last week.
Installed WINCC flex, new location, similar hardware. S7-300 and 1200 comfort HMI.
But now no simulator.
The compatibility tool says WinCC Comfort (TIA Portal) V13.0 SP1 and WinCC flexible 2008 SP3 are compatible.
But Siemens also wrote the compatibility checker..............so.........