What Is a DJVU File?
that have been scanned into a computer.
DjVu files can use the .DJVU or the .DJV file extension.

Lifewire / Tim Fisher
It can also save an open DJVU file to aTXTfile for easy reading without any graphics.
Another free online file converter that’s great for smaller DJVU files isZamzar.
Aside from online DJVU converters, there are, of course, downloadable and installable converters likeCalibre.
Image-only DJVU files aren’t supported.
There’s also an option to define the image quality/compression rate.
Sumatra PDF and DocsPal, mentioned above, can convert DJVU files as well.
Instead,Emsisoft’s free STOP Djvu decryptorshould be able to help fix this issue.
It will decrypt the files so that the originals are restored.