I deleted some customer files on accident. I retrieved them, but I can’t open them with Adobe Reader or Acrobat anymore. What’s wrong with them?
well they are corrupted but if you have restore points you may be able to recover older version.
system restore explorer
Hello, that is one of the possible results when you recover files. It is not uncommon for this to happen. Sometimes you are only able to recover the headers but not the content itself. Have you tried changing the extension, for example to text, and see if you can open it this way? Or probably, you could try a different .pdf reader, maybe it can be able to read the file in a different way.
Recovery software sometime can't recover files successfully, and gives you corrupted recovered files.
so may be it is impossible to read them now.
Try to read it from some other reader.
eg. upload to google docs