Try

Author: ChrisDenton

src/ci/scripts/install-mingw.sh

@@ -43,4 +43,8 @@ if isWindows && isKnownToBeMingwBuild; then
     curl -o mingw.7z "${MIRRORS_BASE}/${mingw_archive}"
     7z x -y mingw.7z > /dev/null
     ciCommandAddPath "$(cygpath -m "$(pwd)/${mingw_dir}/bin")"
+
+    # Workaround for spurious ci failures
+    # see https://rust-lang.zulipchat.com/#narrow/channel/242791-t-infra/topic/Spurious.20bors.20CI.20failures/near/528915775
+    mkdir /c/msys64/home/runneradmin 
 fi