I recently installed the 7.4 version of gVim on a Windows 7 machine. Trying to diff two files from the context-sensitive menu on Windows Explorer, I keep getting the error messages:
E810: Cannot read or write temp files
E97: Cannot create diffs
The two selected files are opened in the two-pane gVim view, and the editor seems to be in diff mode, but the actual differences are not highlighted.
%TMP% environment variables are populated with a valid directory name.
I get the same response when opening the files in a regular gVim session and typing
:diffthis in the command prompt.
This used to work properly with Vim 7.3, but it looked like something was changed in v7.4.
How can I diff the two files?