As you are experiencing an issue in saving the PDFs, please try te steps suggested below:
- In the application, go to Edit > Preferences > General.
- Clear the check box for "Show online storage when opening files" and "Show online storage when saving files"
- Click on OK to save the changes.
Now try to save and check if that works.
Note: If you turn off the online storage options, you won't see the cloud options for opening or saving files in Acrobat DC. We suggest enabling options later on if you wish to save the document to online storage.
Let us know if the issue still persists or you are referring to something else.