One situation I found that will cause "unprotected" problem

IF

  • your system is Windows XP (for me, XP professional SP3+),
  • and it’s in drive C of FAT32,
  • and you want to install avast 2014 (ver. 9.0.2013.292) on drive D of NTFS
    You are to meet the “unprotected” problem like me after a reboot (http://forum.avast.com/index.php?topic=146627.0), I can bet.

But if you change some setting, either the drive format or the installation position of avast (i.e. to C), the problem will not occur. Only the combination above goes wrong.

This is my conclusion after tens of tests, all of which follow the same procedure: setup XP, install avast. I’ve reported it as a bug to the developpers.
Wish the next distribution have this patched.