The message: “Unable to save to ‘(path)’” is that really?
Maybe it is something like:
“Unable to save to ‘C:/Myfolder/foo/bar/myanimation.sifz’”?
It is weird that it doesn’t show the path you saved to.
The relevant part of the code where the error is generated (and further propagated) is this:
// On Win32 platforms, rename() has bad behavior. work around it.
synfig::error("synfig::save_canvas(): Unable to rename file to correct filename, errno=%d",errno);
Maybe some of the mktemp or rename functions has different behavior on windows 8.
This is the story:
Synfig (and Synfig Studio) are made using GNU autotools. This forces to use a script to build the binaries from the source code unless you’re a complete suicide. Build script uses a Cygwin - MinGW toolchain to run the autotools.
In Windows, current master (unstable) branch build script is broken (not sorted out the latest changes) so, to give you a solution I tried to identify the problem on the current official released branch (0.64.1). It turns that the build script is broken too on my 32 bits Windows XP computer (it is complaining when building a third party library).
Apart of that, Windows 8 probably would differ so far from Windows XP and so we cannot assure if the patch would work on Windows 8 unless we directly compile it on Windows 8, what would be difficult until we own one license.