diff --git a/src/libcmd/installables.cc b/src/libcmd/installables.cc
index e15addfae..39162a662 100644
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@@ -736,9 +736,18 @@ std::set<RealisedPath> toRealisedPaths(
                                     output.first);
                             auto outputId = DrvOutput{outputHashes.at(output.first), output.first};
                             auto realisation = store->queryRealisation(outputId);
-                            if (!realisation)
-                                throw Error("cannot operate on an output of unbuilt content-addresed derivation '%s'", outputId.to_string());
-                            res.insert(RealisedPath{*realisation});
+                            if (!realisation) {
+                                // TODO: remove this check once #4725 is fixed
+                                // as we’ll have the guaranty that if
+                                // `output.second` exists, then the realisation
+                                // will be there too
+                                if (output.second)
+                                    res.insert(*output.second);
+                                else
+                                    throw Error("cannot operate on an output of unbuilt content-addresed derivation '%s'", outputId.to_string());
+                            } else {
+                                res.insert(RealisedPath{*realisation});
+                            }
                         }
                         else {
                             // If ca-derivations isn't enabled, behave as if