12.4.1 Unable to start

DOpusInstall.exe
0BA6118F7148AD87E46DD325D522288BD498BD5C

20210712095134

Try a reboot and then a reinstall, and then another reboot.

DOpusInstall-Chinese.exe
SHA1:E48D2D16B4EE54261AA341FC99E5B3B065F349AF
20210712100112

in windows Sandbox New installation, No Simplified Chinese language option.

It looks like the Simplified Chinese language file was corrupted in that installer for some reason. We've just uploaded a new beta and I've checked that it works ok, so please download that and give it a try.