When the External Preview is open I get the following error message *every time* I save: [Document Save Temp File] - ERROR: Unable to Create Temp File: C:\Users... (etc)". When I hit "OK" the External Previewer shows "This program cannot display the webpage". At that point, the page can be saved without the error message, but I have to close and re-open the External Previewer.
I've cleaned out all temp files to no avail. Happens with all pages. Windows 7 64-bit, Editor v 12.9 Build 714. Thanks.

Do you have any scripts on the page that reference external data?

Yes, the page provides multiple links to external sources.

Here's the URL (and other pages) http://www.scimedwriting.com/fundingother.html#

Try commenting one out at a time and you may be able to find which one might be is causing the issue.

Since I'm not at home, I'm working partly out of my dropbox. When editing a file that is stored there, I also tend to get the same error message. I have not had it when working on files stored on my computer or external hdd. I've been using Vista since the latest update of the Editor.

I think Inger may have the answer - thank you, Inger. I also keep my site folder in Dropbox. As a test, I just made a copy to desktop and then edited some files. I got no error messages. I made the exact same changes to the files kept in Dropbox and got the error message every time. So - what is the solution here? Please don't say "don't use Dropbox" as that is not a practical option for me.

I guess the solution will be to move the folders you are working on to your computer, and then when you are done, pop them back into the box.

Disabling Scripts in Preview worked for me, as I was getting the same error and was editing files from my OneDrive folder, so worried was because of that. Phew. Glad sorted, as lovely feature.

Side note: Love the Auto Spell Check function. It drove me insane that Adobe Dreamweaver didn't have that. I think I'll be buying the program when my trial runs out.