The launcher won't launch.

[Raist]

Windows own security will not allow you to reset certain attributes on files in a folder by clearing them on the folder itself like it used to (the option to set the change on all subfolders and files is killed on protected system folders). Read-Only is one such attribute. You will either need to do it as a batch in an elevated CMD prompt using the ATTRIB command with specific switches, or browse down to the files themselves to set the bits that way. You can select all the files you want to change in a folder with the shift or control buttons though for selecting multiple files at once.

You may have fallen prey to the classic Windows NTFS file corruption as well. Might be worth running disk checks to repair any potential file system errors.

The last couple days, several people have noted that it has indeed been an issue with their security software. I haven't run into this problem myself yet... I have my folders and the known SE IP addresses white-listed though, so may be why I haven't seen it since it was an issue with browser plugins back in Beta4. May be worth looking into though--add exceptions for the install folder and your character data folders, then add exceptions for the IP's your system is using (can track them in resmon or netstat via command prompt). Also, make sure your browser add-ins and such are up to date (Flash and such), as this was shown to be an issue back in the fall. It could even be your browser security getting in the way for that matter--could try lowering privacy and other security settings there to see if it resolves it.

A few people found suspicious software under their Add/Remove Programs list that seemed to be interfering as well. May want to run a full malware scan just in case.