diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 50732d5670b..7e615acbfed 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -623,6 +623,28 @@ void LocalStore::registerDrvOutput(const DrvOutputId& id, const DrvOutputInfo &
 
 void LocalStore::registerDrvOutput_(State & state, const StorePath & deriver, const string & outputName, const StorePath & output)
 {
+    // Ensure that we don't register a boguous derivation output.
+    debug("Checking the validiy of the drv output '%s!%s'", printStorePath(deriver), outputName);
+    if (!isValidPath_(state, deriver))
+        settings.requireExperimentalFeature("ca-derivations");
+    else {
+        // Can't use `readDerivation` here as we already hold the lock on the db
+        auto matchingDrv = parseDerivation(
+            *this,
+            readFile(Store::toRealPath(deriver)),
+            Derivation::nameFromPath(deriver)
+        );
+        auto outputsFromDrv = matchingDrv.outputsAndOptPaths(*this);
+        auto currentOutputFromDrv = outputsFromDrv.find(outputName);
+        assert (currentOutputFromDrv != outputsFromDrv.end());
+        if (!currentOutputFromDrv->second.second.has_value()) {
+            // Floating-ca or dependent thereof
+            settings.requireExperimentalFeature("ca-derivations");
+        } else {
+            assert (*currentOutputFromDrv->second.second == output);
+        }
+    }
+
     retrySQLite<void>([&]() {
         state.stmtAddDerivationOutput.use()
             (printStorePath(deriver))