diff --git a/lix/libcmd/command.cc b/lix/libcmd/command.cc
index 812f8b446..4082ddb0d 100644
--- a/lix/libcmd/command.cc
+++ b/lix/libcmd/command.cc
@@ -75,6 +75,15 @@ CopyCommand::CopyCommand()
     });
 }
 
+void CopyCommand::run()
+{
+    if (requireStore && srcUri.empty() && dstUri.empty()) {
+        throw UsageError("you must pass '--from' and/or '--to'");
+    }
+
+    StoreCommand::run();
+}
+
 ref<Store> CopyCommand::createStore(AsyncIoRoot & in)
 {
     return srcUri.empty() ? StoreCommand::createStore(in) : in.blockOn(openStore(srcUri));
@@ -82,9 +91,6 @@ ref<Store> CopyCommand::createStore(AsyncIoRoot & in)
 
 ref<Store> CopyCommand::getDstStore()
 {
-    if (srcUri.empty() && dstUri.empty())
-        throw UsageError("you must pass '--from' and/or '--to'");
-
     return aio().blockOn(dstUri.empty() ? openStore() : openStore(dstUri));
 }
 
diff --git a/lix/libcmd/command.hh b/lix/libcmd/command.hh
index da8cc4934..9b242e159 100644
--- a/lix/libcmd/command.hh
+++ b/lix/libcmd/command.hh
@@ -56,9 +56,11 @@ private:
 struct CopyCommand : virtual StoreCommand
 {
     std::string srcUri, dstUri;
+    bool requireStore = true;
 
     CopyCommand();
 
+    void run() override;
     ref<Store> createStore(AsyncIoRoot & in) override;
 
     ref<Store> getDstStore();
diff --git a/lix/nix/make-content-addressed.cc b/lix/nix/make-content-addressed.cc
index 9074e6f3b..4912a6556 100644
--- a/lix/nix/make-content-addressed.cc
+++ b/lix/nix/make-content-addressed.cc
@@ -12,6 +12,7 @@ struct CmdMakeContentAddressed : virtual CopyCommand, virtual StorePathsCommand,
     CmdMakeContentAddressed()
     {
         realiseMode = Realise::Outputs;
+        requireStore = false;
     }
 
     std::string description() override
@@ -28,7 +29,7 @@ struct CmdMakeContentAddressed : virtual CopyCommand, virtual StorePathsCommand,
 
     void run(ref<Store> srcStore, StorePaths && storePaths) override
     {
-        auto dstStore = aio().blockOn(dstUri.empty() ? openStore() : openStore(dstUri));
+        auto dstStore = getDstStore();
 
         auto remappings = aio().blockOn(makeContentAddressed(*srcStore, *dstStore,
             StorePathSet(storePaths.begin(), storePaths.end())));