@Laktoz_AJ Hey. Corruption has nothing to do with foreign characters anymore, this was fixed in previous versions and now the sound files are internally renamed when imported. However if you’re using Windows10 that’s the real source of the problem as we’ve discovered that it randomly denies saving the files when you are not the admin of your system, thus corrupting your files.
We have a guide to prevent these issues but we don’t have a definite fix: Pencil2D Project File Corruption Prevention / Partial Recovery Guide
Indeed in the guide it says that you have to turn the PCLX to ZIP to extract the file, but this is done by changing the file extension, not by zipping the file (which I’m assuming was what happened). Just in case the guide has a video tutorial on how to do this and extract the images.
In the guide the process is outlined but If you want share the PCLX file with us here either via dropbox, google drive or wetransfer and post the link. We’ll gladly inspect the file and recover whatever is still inside, however do know that it’s possible that some images were lost, particularly form the beginning of the animation.