diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index e70103f47..769b3be7f 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -275,7 +275,7 @@ void LocalStore::registerValidPath(const Path & path,
 }
 
 
-void LocalStore::registerValidPath(const ValidPathInfo & info)
+void LocalStore::registerValidPath(const ValidPathInfo & info, bool ignoreValidity)
 {
     Path infoFile = infoFileFor(info.path);
 
@@ -300,7 +300,7 @@ void LocalStore::registerValidPath(const ValidPathInfo & info)
         if (!refs.empty()) refs += " ";
         refs += *i;
 
-        if (*i != info.path && !isValidPath(*i))
+        if (!ignoreValidity && *i != info.path && !isValidPath(*i))
             throw Error(format("cannot register `%1%' as valid, because its reference `%2%' isn't valid")
                 % info.path % *i);
 
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 65bec1047..ead49baae 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -121,7 +121,7 @@ private:
     /* Store paths for which the referrers file must be purged. */
     PathSet delayedUpdates;
 
-    void registerValidPath(const ValidPathInfo & info);
+    void registerValidPath(const ValidPathInfo & info, bool ignoreValidity = false);
 
     ValidPathInfo queryPathInfo(const Path & path);
 
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 0f00b7037..a50dcf645 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -267,6 +267,7 @@ struct ValidPathInfo
     Hash hash;
     PathSet references;
     time_t registrationTime;
+    ValidPathInfo() : registrationTime(0) { }
 };
 
 typedef list<ValidPathInfo> ValidPathInfos;
diff --git a/src/libstore/upgrade-schema.cc b/src/libstore/upgrade-schema.cc
index 540a51b91..b3d691485 100644
--- a/src/libstore/upgrade-schema.cc
+++ b/src/libstore/upgrade-schema.cc
@@ -58,19 +58,20 @@ void LocalStore::upgradeStore12()
     nixDB.enumTable(noTxn, dbValidPaths, paths);
     
     for (Paths::iterator i = paths.begin(); i != paths.end(); ++i) {
-        PathSet references;
-        Paths references2;
-        nixDB.queryStrings(noTxn, dbReferences, *i, references2);
-        references.insert(references2.begin(), references2.end());
+        ValidPathInfo info;
+        info.path = *i;
+        
+        Paths references;
+        nixDB.queryStrings(noTxn, dbReferences, *i, references);
+        info.references.insert(references.begin(), references.end());
         
         string s;
         nixDB.queryString(noTxn, dbValidPaths, *i, s);
-        Hash hash =parseHashField(*i, s);
+        info.hash = parseHashField(*i, s);
         
-        Path deriver;
-        nixDB.queryString(noTxn, dbDerivers, *i, deriver);
+        nixDB.queryString(noTxn, dbDerivers, *i, info.deriver);
         
-        registerValidPath(*i, hash, references, deriver);
+        registerValidPath(info, true);
         std::cerr << ".";
     }