i can not crop and save files.
Russ Turrentine commented
I believe what they mean is that they can't crop and save the file without the information that was cropped out. People want to crop something and have it totally delete anything including white space outside the crop. That should reduce the file size. Just hiding something is not what people want. Think about cropping in Paint or other image program. Anything outside the crop is deleted entirely.
Please elaborate your issue in detail.
If possible please share the file with us.
Also please let us know your OS and Acrobat DC version.