Comment 52 for bug 804936

Here is my experience with this issue and Zim 0.65 on Windows. I have a few notebooks on network shares and Dropbox. I never have a problem in Linux (NFS or Dropbox), or on Windows 10 with a notebook in Dropbox. I only get this error in Windows with a network drive (mapped to a Samba share). This hasn't always happened, so I believe a Zim update kicked it off. Here is an example error:
>>>
[Error 2] The system cannot find the file specified: u'P:\\Notebooks\\Notes\\00_Notes_TODO.txt.zim-orig~'

To continue you can save a copy of this page or discard
any changes. If you save a copy changes will be also
discarded, but you can restore the copy later.
>>>
This only happens if I issue a save command (Ctrl+S). If I wait for auto-save, it works fine. If I hit Cancel on the error dialog and wait for auto-save, it gets saved.

Here is the other interesting twist. If I launch Zim and open the notebook above on the share, it will start out read-only with the Notebook Editable option disabled, as in I cannot toggle the option. Now, I open another notebook on Dropbox, then re-open the original notebook (same instance of Zim the entire time). The notebook will still be read-only, yet now I can toggle the Notebook Editable option. If I click the button, I can now edit the notebook, but Ctrl+S causes the error above.

Let me know if you'd like another bug report for this other odd behavior, but it seems somehow related to [Error 2] in my case.