Кстати, ASSOC и FTYPE обращаются не HKCR, а напрямую к HKLM\Software\Classes, т.е. не видят настройки на уровне отдельного пользователя
Решил убедится, что оно так. С помощью ProcMon отфильтровал обращения к реестру cmd.exe при запуске assoc/ftype. Все таки читает из HKCR\Classes
assoc .html
"Time of Day","Process Name","PID","Operation","Path","Result","Detail"
"13:10:53,9223164","cmd.exe","23652","RegQueryKey","HKLM","SUCCESS","Query: HandleTags, HandleTags: 0x0"
"13:10:53,9223632","cmd.exe","23652","RegOpenKey","HKCR","SUCCESS","Desired Access: Maximum Allowed, Granted Access: All Access"
"13:10:53,9224125","cmd.exe","23652","RegQueryKey","HKCR","SUCCESS","Query: HandleTags, HandleTags: 0x0"
"13:10:53,9224786","cmd.exe","23652","RegOpenKey","HKCR\.html","SUCCESS","Desired Access: Query Value"
"13:10:53,9225209","cmd.exe","23652","RegQueryValue","HKCR\.html\(Default)","SUCCESS","Type: REG_SZ, Length: 18, Data: htmlfile"
"13:10:53,9225607","cmd.exe","23652","RegQueryValue","HKCR\.html\(Default)","SUCCESS","Type: REG_SZ, Length: 18, Data: htmlfile"
"13:10:53,9225911","cmd.exe","23652","RegCloseKey","HKCR\.html","SUCCESS",""
"13:10:53,9227249","cmd.exe","23652","RegCloseKey","HKCR","SUCCESS",""
ftype htmlfile
"Time of Day","Process Name","PID","Operation","Path","Result","Detail"
"13:06:49,4887237","cmd.exe","23652","RegQueryKey","HKLM","SUCCESS","Query: HandleTags, HandleTags: 0x0"
"13:06:49,4887623","cmd.exe","23652","RegOpenKey","HKCR","SUCCESS","Desired Access: Maximum Allowed, Granted Access: All Access"
"13:06:49,4888074","cmd.exe","23652","RegQueryKey","HKCR","SUCCESS","Query: HandleTags, HandleTags: 0x0"
"13:06:49,4888403","cmd.exe","23652","RegOpenKey","HKCR\htmlfile\Shell\Open\Command","SUCCESS","Desired Access: Maximum Allowed, Granted Access: All Access"
"13:06:49,4888653","cmd.exe","23652","RegQueryKey","HKCR","SUCCESS","Query: HandleTags, HandleTags: 0x0"
"13:06:49,4888891","cmd.exe","23652","RegOpenKey","HKCR\htmlfile\Shell\Open\Command","SUCCESS","Desired Access: Query Value"
"13:06:49,4889162","cmd.exe","23652","RegQueryValue","HKCR\htmlfile\shell\open\command\(Default)","SUCCESS","Type: REG_SZ, Length: 106, Data: ""C:\Program Files\Internet Explorer\iexplore.exe"" %1"
"13:06:49,4889860","cmd.exe","23652","RegQueryValue","HKCR\htmlfile\shell\open\command\(Default)","SUCCESS","Type: REG_SZ, Length: 106, Data: ""C:\Program Files\Internet Explorer\iexplore.exe"" %1"
"13:06:49,4890139","cmd.exe","23652","RegCloseKey","HKCR\htmlfile\shell\open\command","SUCCESS",""
"13:06:49,4891453","cmd.exe","23652","RegCloseKey","HKCR","SUCCESS",""
( 2 * b ) || ! ( 2 * b )