Sorry for the delay in response.
As you have mentioned that you get an error while saving the file, it is an issue with all the files?
The file that you open in the application, is it saved on your system or on a server?
What is the dot version of the application you are using on your system? Take help of the steps mentioned here Identify the product and its version for Acrobat and Reader DC to check that.
Also, share the exact steps you do that results in the error message.
Please share the information asked above.
Let us know if you have any question.
After my computer did the adobe update on monday, it stopped letting me save. I get the error message, " The file may be a read only, or another user has it open. Please save the document with a different name or in a different location." It is not read only no one else has it open, and I tried all of the above. It also gives me an error, "The document could not be saved. This file could not be found." I have been using these same files, and they worked fine until the new adobe update. I have tried disabling the detail pane and preview pane under file explorer with no resolution. Everything else on my computer works, its just when I am trying to save an adobe file, and I did not have this issue until the new adobe update on monday. I also tried to install the patch for the nov update, and that did not help either. I have also went under properties - general - and made sure that anything that said could storage was disabled. I have tried everything in the adobe forums and anything I could find on the internet and still can not save like I could, before the adobe update. I just now tried Edit>Preferences>Documents - uncheck "Save As optimizes for Fast Web View", and that did not help either. I have also tried Tried Edit/Preferences/Security(Enhanced) unchecked Enable Enhanced Security. I am not using Details View.
I have this exact same problem. Except that, after I exited out of the error message, my whole document was deleted, and I have lost close to 20 hours of work. I am devastated and so very angry. This file had been saving just fine until I tried to save it today (1/17/18). The file no longer exists. I have a MacBook Air and I am operating on Sierra 10.12.6. I had been saving onto Microsoft One Drive. And of course, as soon as Adobe lost my document, that damn cloud began to sync with my computer, and voila, now the document doesn't exist in my cloud either. Absolutely gone. I have three more open documents on Adobe. I tried to save them also, and I also got the error message for each of them, "The file may be a read only, or another user has it open. Please save the document with a different name or in a different location." After I exited this message, my entire document went blank, all the text gone with only the yellow highlight remaining. To reiterate I had just a blank document with lines of yellow in the areas where the text used to be. I clicked revert and was able to "fix" the documents (although I am still unable to save them). But the one large file, the one I lost, when I tried to click revert on that one (seeing as it was able to restore the other documents) is when it completely disappeared. My OneDrive has all these documents, but all the comments and highlight (the actual work invested in them) are gone and they have all been reverted to the day I first downloaded them (even though reverting is supposed to revert to the last save point). The last three remaining documents are still open on my computer, but I am unable to save them and my One Drive doesn't have them saved. So for me, any and all pdf files open in Adobe refuse to save. I have the Adobe Acrobat Reader DC 2017 Release Version: 2017.012.20098. Sorry for hijacking this question. I have never used the forums before and I don't know how to make my own post. I am just encountering the exact same problem.