How to get files from cooked game?

Hi!
Yesterday a virus encrypted many of my files and files of my game too. It renamed all files adding .id-A0766CC1.[dcr@airmail.cc].combo at the end of every file.
renaming it to previous state doesn’t work.
But i have cooked version of game. How can I “uncook” it, so I can have it files back?
There is a .pak file in game files, so I tried unpacking it with UnrealPak.exe, but none of unpack files is working. When opening HSPro.uproject I get an error:
Failed to load map!
…/…/…/…/…/…/p/HSPro/Content/TopDownBP/Maps/TopDownExampleMap.umap appears to be an asset file.
And when project opens it don’t see any project files, only empty folders.

Cooked files are get rid of any content that is used for development and stuff needed by the editor aspecially when you do shipping build. Cooking also process files to there terget distribution formats, for example PCM sounds used by editor are being encoded to Vobis OGG format. So they most likely won’t work with editor as they incomplete.

So I’ll have to do everything from scratch?

You just need Umodel by Gildor. There is even an -uncook option!