After clicking OK again, Animate then shows me a black screen. The File, Edit, View, and everything else is still there. I tried finding how to fix this issue for the past hour but I eventually gave up.
make sure you have the latest version of animate. if you do, your fla is corrupt.
you can look for a recovery file* and you can try repairing by renaming the fla to a rar, using winrar to repair, renaming the repaired rar to a fla and trying to open the fla in animate.
win: C:\Users\<username>\AppData\Local\Adobe\<animate version>\en_US\Configuration
mac: ~/Library/Application Support/Adobe/<animate/flash version>/en_US/Configuration/
When I tried that all it did was delete all my symbols and scenes and just left me with images and sound files
I tried this method but it doesn't work in my case unfortunately. This means no hopes to recover my .fla anymore, right?
correct. that method usually fails, but it's the only (afaik) "repair" method.
however, repair is not the only way to get a working fla. you may have a working backup (either generated by animate automatically or by you manually) and
1. with as3 projects, you may have a working swf which can often be decompiled to a working fla.
2. with html5/canvas, you can manually edit (in any plain text editor) the js and/or html file. they'll not be corrupted (though they're not easy to work with even with js,html expertise).