diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index f352fd7b6..22ef24502 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,4 +1,5 @@
 # @author Oliver Thomson Brown
+# @author Tyson Jones (patched MSVC and test discovery)
 
 add_executable(tests
   main.cpp
@@ -19,5 +20,5 @@ if (QUEST_ENABLE_DEPRECATED_API)
   add_subdirectory(deprecated)
 endif()
 
-# let Catch2 register all tests with CTest
-catch_discover_tests(tests)
+# defer test discovery, so that (e.g.) MPI libs aren't loaded during build
+catch_discover_tests(tests DISCOVERY_MODE PRE_TEST)
diff --git a/tests/deprecated/CMakeLists.txt b/tests/deprecated/CMakeLists.txt
index 2a97b602c..570561332 100644
--- a/tests/deprecated/CMakeLists.txt
+++ b/tests/deprecated/CMakeLists.txt
@@ -1,5 +1,6 @@
 # @author Oliver Thomson Brown
 # @author Erich Essmann (patched MPI)
+# @author Tyson Jones (deferred test discovery)
 
 add_executable(dep_tests
     test_main.cpp
@@ -18,4 +19,4 @@ if (QUEST_ENABLE_MPI)
     target_link_libraries(dep_tests PRIVATE MPI::MPI_CXX)
 endif()
 
-catch_discover_tests(dep_tests)
\ No newline at end of file
+catch_discover_tests(dep_tests DISCOVERY_MODE PRE_TEST)
\ No newline at end of file