For information I found the corrupted file, it was temp_options.lua
The beginning of the file is strange:
temp_options =
{
["lastSkin"] =
{
}, -- end of ["lastSkin"]
["lastCampaign"] =
{
["CLSID"] = "Su-25T by Eagle Dynamics1",
["campLast"] = -1,
}, -- end of ["lastCampaign"]
Without ["lastCampaign"] lines in the file, there is no freeze loading campaign choice screen.
Now I need to figure out why I have no SU-25T campaign despite that the files for the campaign are available in Su-25T\Missions\EN\Campaigns\ !!!