diff --git a/cmake/FindKRB5.cmake b/cmake/FindKRB5.cmake
index ee627089b..c7da561b5 100644
--- a/cmake/FindKRB5.cmake
+++ b/cmake/FindKRB5.cmake
@@ -150,17 +150,26 @@ endfunction()
 # * Then try to find krb5-config (generic, krb5-config.mit and last krb5-config.heimdal)
 find_package(PkgConfig REQUIRED)
 
+unset(KRB5_MIT_FOUND CACHE)
+unset(KRB5_HEIMDAL_FOUND CACHE)
+unset(KRB5_ANY_FOUND CACHE)
+unset(KRB5_FOUND CACHE)
+unset(KRB5_VERSION CACHE)
+unset(KRB5_FLAVOUR CACHE)
+
 if(KRB5_ROOT_CONFIG)
 
 elseif(KRB5_ROOT_FLAVOUR)
+  message("krb5: searching with preference for [${KRB5_ROOT_FLAVOUR}]...")
   if(KRB5_ROOT_FLAVOUR STREQUAL "Heimdal")
-    pkg_check_modules(KRB5_HEIMDAL heimdal-krb5)
+    pkg_check_modules(KRB5_HEIMDAL heimdal-krb5 REQUIRED)
   elseif(KRB5_ROOT_FLAVOUR STREQUAL "MIT")
-    pkg_check_modules(KRB5_HEIMDAL mit-krb5)
+    pkg_check_modules(KRB5_MIT mit-krb5 REQUIRED)
   else()
     message(FATAL_ERROR "Invalid KRB5_ROOT_FLAVOUR=${KRB5_ROOT_FLAVOUR}, only 'MIT' or 'Heimdal' are supported")
   endif()
 else()
+  message("krb5: searching without preference...")
   pkg_check_modules(KRB5_MIT mit-krb5)
   pkg_check_modules(KRB5_HEIMDAL heimdal-krb5)
 endif()