About 50% of the time when building a small sample project named Some Test Language in Spoofax
Nighly in the new debugging Eclipse instance, I get this error and the build fails:

runtime-Spoofax\Some Test Language\build.generated.xml:560: Unable to rename old file
(runtime-Spoofax\Some Test Language\include\some_test_language-java.jar) to temporary file

Building a second time often succeeds. This happens since I’m using Spoofax Nightly, it never
happend before when I was using Spoofax Stable and earlier.

Submitted by D. Pelsmaeker on 26 September 2014 at 13:00

Didn’t you fix this Eduardo?

Yes, I think this was happening on Windows laptops. The fix I did was to always delete the file before building the project.