diff --git a/ports/eigen3/CONTROL b/ports/eigen3/CONTROL
index 2586620a037..3993a35f03f 100644
--- a/ports/eigen3/CONTROL
+++ b/ports/eigen3/CONTROL
@@ -1,3 +1,3 @@
 Source: eigen3
-Version: 3.3.7
+Version: 3.3.7-1
 Description: C++ template library for linear algebra: matrices, vectors, numerical solvers, and related algorithms.
diff --git a/ports/eigen3/portfile.cmake b/ports/eigen3/portfile.cmake
index 9ba26835067..31806319f40 100644
--- a/ports/eigen3/portfile.cmake
+++ b/ports/eigen3/portfile.cmake
@@ -1,5 +1,12 @@
 include(vcpkg_common_functions)
 
+string(LENGTH "${CURRENT_BUILDTREES_DIR}" BUILDTREES_PATH_LENGTH)
+if(BUILDTREES_PATH_LENGTH GREATER 37 AND CMAKE_HOST_WIN32)
+    message(WARNING "eigen3's buildsystem uses very long paths and may fail on your system.\n"
+        "We recommend moving vcpkg to a short path such as 'C:\\src\\vcpkg' or using the subst command."
+    )
+endif()
+
 vcpkg_from_github(
     OUT_SOURCE_PATH SOURCE_PATH
     REPO eigenteam/eigen-git-mirror