For determining font metrics, the pgf backend is communicating with a spawned LaTeX instance. A problem on Windows is that a process spawned by subprocess automatically inherits all open file descriptors and keeps them open as long as the subprocess is running. As a result, the application will hold on to the files and moving or deleting them may fail. There is an option called close_fds that prevents this from happening, but if you enable that option there is no way of communicating with the process.
I don't see how this can be done with stdin/stdout on Windows, so the only solution appears to be the development of a own simple inter-process communication and not to inherit fds when spawning the subprocess.
backend_pgf: add a remark concerning #1324 to the doc, some cleanup
@pwuertz - how does this issue stand? Has this been addressed, or indeed, has anybody come across this issue?
No, this problem is very specific and most of the time you wouldn't notice it at all. The latest fix I added back then at least reduces the problem to long running applications that won't be able to delete the temporary directories created for compiling figures.
It is a known limitation on windows (I've raged around in #1286 about that) for which you'll find a few discussions on stackoverflow - but no solution so far.
I was just going to ask that you add a note to the docs, but I see it's already there...
While I understand a "real" solution hasn't been found, if we feel the research has been exhausted, maybe we close this just to keep the number of open bugs down?
Ok, closing this issue as 'wontfix'.
Good news! It seems that the inherited file descriptor bug is going to be solved in the upcoming python version 3.4.