I don't have any idea how it happened, but I have several document and PDF files that are now saved as CCleaner. I can't fix it. I can't open any using other formats. I can't open them directly as saved. I've lost MUCH IMPORTANT information that I can't recover. How do I fix this?
They are not lost, a setting has been changed and you can change it back quite simply.
To reassociate your PDF's back to opening with Adobe, or whatever you want to open them with,
- Right click on any PDF file.
- Select 'Open With'.
- Select 'Chose another app'.
- Select the app you want to use to view PDFs.
- Tick the box 'Always use this app to open .....'
- Click 'OK'
See the screenshots in this post: https://forum.piriform.com/topic/55455-ccleaner-browser-pdf-files/?tab=comments#comment-310603