I just started working with a new desktop pc with adobe flash professional cs6. When I try to open flash files (.fla extension) that have been created / edited on another computer, I get the "unexpected file format" error. However, I can open the .as file that belongs to the fla without any problems at all.
I´ve tried the WinRAR repair solution, unfortunately I am unable to open the fla file (even if I rename it to rar/zip) since I get an error message telling me that the file is damaged.
Thanks for your help,
Do you have any earlier version of Flash such as the one that originally created the FLA available? Does it open in that? If so you should "Save Down" the document to Flash CS4, then try to re-open.
FYI, you should be able to rename it to .zip and open it up. A FLA is just a zip file containing a bunch of files. If you can't even open that with .zip there may actually be a chance your file is damaged.