diff --git a/INSTALL.md b/INSTALL.md
index 5be4905635..bb597336e4 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -40,7 +40,7 @@ Both methods are supported. However, for most users we _strongly_ recommend to b
   - Boost.Container: header-only
   - Boost.Test: header-only or (optionally) as a compiled library, *only used for unit testing*
   - Boost.Range: header-only, *only used for unit testing*
-- [BTAS](http://github.com/ValeevGroup/BTAS), tag fba66ad9881ab29ea8df49ac6a6006cab3fb3ce5 . If usable BTAS installation is not found, TiledArray will download and compile
+- [BTAS](http://github.com/ValeevGroup/BTAS), tag 2917aa21465a93ae6f399874f247b5fe31d6b693 . If usable BTAS installation is not found, TiledArray will download and compile
   BTAS from source. *This is the recommended way to compile BTAS for all users*.
 - [MADNESS](https://github.com/m-a-d-n-e-s-s/madness), tag 0b44ef319643cb9721fbe17d294987c146e6460e .
   Only the MADworld runtime and BLAS/LAPACK C API component of MADNESS is used by TiledArray.
diff --git a/cmake/modules/FindOrFetchBoost.cmake b/cmake/modules/FindOrFetchBoost.cmake
index c63bdd0819..6ddb2a3b8d 100644
--- a/cmake/modules/FindOrFetchBoost.cmake
+++ b/cmake/modules/FindOrFetchBoost.cmake
@@ -5,6 +5,16 @@ endif()
 
 # try find_package
 if (NOT TARGET Boost::boost)
+
+  # detect which Boost targets I already have
+  foreach(tgt boost;headers;${Boost_BTAS_DEPS_LIBRARIES})
+    if (TARGET Boost::${tgt})
+      set(ta_imported_boost_${tgt} 0)
+    else()
+      set(ta_imported_boost_${tgt} 1)
+    endif()
+  endforeach()
+
   include(FindPackageRegimport)
   find_package_regimport(Boost ${TA_TRACKED_BOOST_VERSION} QUIET)
   if (TARGET Boost::boost)
@@ -14,7 +24,7 @@ if (NOT TARGET Boost::boost)
   # Boost::* targets by default are not GLOBAL, so to allow users of TA to safely use them we need to make them global
   # more discussion here: https://gitlab.kitware.com/cmake/cmake/-/issues/17256
   foreach(tgt boost;headers;${Boost_BTAS_DEPS_LIBRARIES})
-    if (TARGET Boost::${tgt})
+    if (TARGET Boost::${tgt} AND ta_imported_boost_${tgt})
       get_target_property(_boost_tgt_${tgt}_is_imported_global Boost::${tgt} IMPORTED_GLOBAL)
       if (NOT _boost_tgt_${tgt}_is_imported_global)
         set_target_properties(Boost::${tgt} PROPERTIES IMPORTED_GLOBAL TRUE)
diff --git a/external/.gitignore b/external/.gitignore
deleted file mode 100644
index 3dfc5d72aa..0000000000
--- a/external/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-src/
-build/
diff --git a/external/versions.cmake b/external/versions.cmake
index 4518827d2d..ea25d3b1c6 100644
--- a/external/versions.cmake
+++ b/external/versions.cmake
@@ -24,8 +24,8 @@ set(TA_TRACKED_MADNESS_PREVIOUS_TAG 29a2bf3d3c2670c608b7bfdf2299d76fbc20e041)
 set(TA_TRACKED_MADNESS_VERSION 0.10.1)
 set(TA_TRACKED_MADNESS_PREVIOUS_VERSION 0.10.1)
 
-set(TA_TRACKED_BTAS_TAG fba66ad9881ab29ea8df49ac6a6006cab3fb3ce5)
-set(TA_TRACKED_BTAS_PREVIOUS_TAG f7c9385348ea87202a887504e2be8bc477efdc3f)
+set(TA_TRACKED_BTAS_TAG 2917aa21465a93ae6f399874f247b5fe31d6b693)
+set(TA_TRACKED_BTAS_PREVIOUS_TAG fba66ad9881ab29ea8df49ac6a6006cab3fb3ce5)
 
 set(TA_TRACKED_LIBRETT_TAG 68abe31a9ec6fd2fd9ffbcd874daa80457f947da)
 set(TA_TRACKED_LIBRETT_PREVIOUS_TAG 7e27ac766a9038df6aa05613784a54a036c4b796)