diff --git a/lang/cpp/src/key.cpp b/lang/cpp/src/key.cpp
index 61b3eb77..8fc266ff 100644
--- a/lang/cpp/src/key.cpp
+++ b/lang/cpp/src/key.cpp
@@ -347,6 +347,9 @@ const Key &Key::mergeWith(const Key &other)
 
 void Key::update()
 {
+    if (isNull() || !primaryFingerprint()) {
+        return;
+    }
     auto ctx = Context::createForProtocol(protocol());
     if (!ctx) {
         return;
diff --git a/lang/cpp/src/verificationresult.cpp b/lang/cpp/src/verificationresult.cpp
index 2c42d074..fa8237ad 100644
--- a/lang/cpp/src/verificationresult.cpp
+++ b/lang/cpp/src/verificationresult.cpp
@@ -406,7 +406,7 @@ GpgME::Key GpgME::Signature::key(bool search, bool update) const
     }
 
     GpgME::Key ret = key();
-    if (ret.isNull() && search) {
+    if (ret.isNull() && search && fingerprint ()) {
         auto ctx = Context::createForProtocol (d->proto);
         if (ctx) {
             ctx->setKeyListMode(KeyListMode::Local |