I recently wanted to install AVG antivirus on my Windows 7 64-bit.
The installer failed with and error message saying that it cannot access the 'sc.dat' file in the AVG destination folder.
I have initially blamed it for a broken installer, but then verified that... I cannot create a file whose name starts with 'sc.dat' anywhere! Creating files with other names works perfectly fine.
The error I'm getting is '5: access is denied'.
Tried to do the same in C++ program and debug to get the root cause, but ended up in a syscall #0x52 which cannot be traced with user-level debugger and that syscall is where the failure happens (verified that other names passes through that syscall with no error).
I thought that maybe some sort of weird permissions, but did not notice anything strange in folders where I have attempted to write the file.
Anyone having any ideas?