Compiling FF78: "Could not find artifacts for ... "win32-minidump-stackwalk""

So I’m trying to compile the newest FF (W7x64).

hg pull && hg update

Now as usual, mach annoyingly complains about some compiler being outdated, so as every month I have to

mach bootstrap

I select 2 (normal FF), it downloads “node.tar.bz2”, then “fix-stacks.tar.bz2” and then crashes with Could not find artifacts for a toolchain build named win32-minidump-stackwalk.

So what exactly does it want me to do and why does this happen?

mach clobber python - does not work.

Thank you

Full log:

 0:05.83 Setting up artifact node.tar.bz2
 0:05.84 Using artifact from local cache: ...\mozbuild\toolchains\97a30da439a065e2-node.tar.bz2
 0:05.93 rm tree: ...\mozbuild\node
 0:09.68 untarring "...\mozbuild\node.tar.bz2"
 0:05.72 Setting up artifact fix-stacks.tar.bz2
 0:05.73 Using artifact from local cache: ...\mozbuild\toolchains\7857866b42f45825-fix-stacks.tar.bz2
 0:05.79 rm tree: ...\mozbuild\fix-stacks
 0:05.79 untarring "...\mozbuild\fix-stacks.tar.bz2"
 0:05.53 Could not find artifacts for a toolchain build named `win32-minidump-stackwalk`. Local commits, dirty/stale files, and other change s in your checkout may cause this error. Make sure you are on a fresh, current checkout of mozilla-central. If you are already, you may be a ble to avoid this error by running `mach clobber python`. Beware that commands like `mach bootstrap` and `mach artifact` are unlikely to wor k on any versions of the code besides recent revisions of mozilla-central.
Error running mach:


The error occurred in code that was called by the mach command. This is either a bug in the called code itself or in the way that mach is calling it. You can invoke |./mach busted| to check if this issue is already on file. If it isn't, please use |./mach busted file| to report it. If |./mach busted| is misbehaving, you can also inspect the dependencies of bug 1543241.

If filing a bug, please include the full output of mach, including this error message.

The details of the failure are as follows:

subprocess.CalledProcessError: Command '['...\\mozilla-build\\python3\\python3.exe', '...\\mozilla-source\\mozilla-relea
se\\mach', 'artifact', 'toolchain', '--from-build', 'win32-minidump-stackwalk']' returned non-zero exit status 1.

  File "...\mozilla-release\python/mozboot/mozboot/", line 44, in bootstrap
  File "...\mozilla-release\python/mozboot\mozboot\", line 544, in bootstrap
  File "...\mozilla-release\python/mozboot\mozboot\", line 400, in maybe_install_private_packages_or_exit
    self.instance.ensure_minidump_stackwalk_packages(state_dir, checkout_root)
  File "...\mozilla-release\python/mozboot\mozboot\", line 156, in ensure_minidump_stackwalk_packages

  File "...\mozilla-release\python/mozboot\mozboot\", line 358, in install_toolchain_artifact
    subprocess.check_call(cmd, cwd=state_dir)
  File "...\mozilla-build\python3\lib\", line 291, in check_call
    raise CalledProcessError(retcode, cmd)

Well I just deleted the whole source folder and re-downloaded it and it works now for whatever reason.