diff --git a/src/lib/opaque-holder.hpp b/src/lib/opaque-holder.hpp
index 6e1fe9689..4be97561c 100644
--- a/src/lib/opaque-holder.hpp
+++ b/src/lib/opaque-holder.hpp
@@ -75,6 +75,7 @@
 #include <utility>
 #include <type_traits>
 #include <boost/noncopyable.hpp>
+#include <boost/lexical_cast.hpp>
 
 
 namespace lib {
@@ -730,7 +731,9 @@ namespace lib {
         {
           if (sizeof(SUB) > maxSiz_)
             throw error::Fatal("Unable to implant implementation object of size "
-                               "exceeding the pre-established storage buffer capacity."
+                               "exceeding the pre-established storage buffer capacity. "
+                               +boost::lexical_cast<std::string>(sizeof(SUB)) + " > "
+                               +boost::lexical_cast<std::string>(maxSiz_)
                               ,error::LUMIERA_ERROR_CAPACITY);
           
           using Holder = InPlaceBuffer<BA, sizeof(SUB)>;
diff --git a/tests/core/proc/asset/entry-id-test.cpp b/tests/core/proc/asset/entry-id-test.cpp
index 516253de8..3c0734c0f 100644
--- a/tests/core/proc/asset/entry-id-test.cpp
+++ b/tests/core/proc/asset/entry-id-test.cpp
@@ -175,8 +175,11 @@ namespace test{
           
           cout << showSizeof<ForkID>() << endl;
           cout << showSizeof<BareEntryID>() << endl;
+          cout << showSizeof<lumiera_uid>() << endl;
+          cout << showSizeof<string>() << endl;
+          cout << showSizeof<void*>() << endl;
           CHECK (sizeof(ForkID) == sizeof(BareEntryID));
-          CHECK (sizeof(ForkID) == sizeof(lumiera_uid) + sizeof(void*));
+          CHECK (sizeof(ForkID) == sizeof(lumiera_uid) + sizeof(string));
         }
       
       
diff --git a/tests/library/diff/diff-complex-application-test.cpp b/tests/library/diff/diff-complex-application-test.cpp
index aa5bdd033..f0c0f1f0f 100644
--- a/tests/library/diff/diff-complex-application-test.cpp
+++ b/tests/library/diff/diff-complex-application-test.cpp
@@ -272,7 +272,7 @@ namespace test{
         friend constexpr size_t
         treeMutatorSize (const Opaque*)
         {
-          return 350;
+          return 430;
         }
       };