diff --git a/libcockatrice_card/libcockatrice/card/database/card_database.cpp b/libcockatrice_card/libcockatrice/card/database/card_database.cpp
index 443552eb3..56f228c69 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/card_database.cpp
@@ -241,6 +241,18 @@ void CardDatabase::addFormat(const FormatRulesPtr &format)
 
 void CardDatabase::swapInDatabaseData(CardDatabaseData data)
 {
+    for (const auto &card : cards) {
+        for (auto *rel : card->getRelatedCards()) {
+            rel->deleteLater();
+        }
+        for (auto *rel : card->getReverseRelatedCards()) {
+            rel->deleteLater();
+        }
+        for (auto *rel : card->getReverseRelatedCards2Me()) {
+            rel->deleteLater();
+        }
+    }
+
     cards = std::move(data.cards);
     simpleNameCards = std::move(data.simpleNameCards);
     sets = std::move(data.sets);
diff --git a/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp b/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp
index d4dc567b6..8e5a83205 100644
--- a/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp
+++ b/libcockatrice_card/libcockatrice/card/database/card_database_loader.cpp
@@ -2,6 +2,7 @@
 
 #include "card_database.h"
 #include "card_database_cache.h"
+#include "parser/card_database_parser.h"
 #include "parser/cockatrice_xml_3.h"
 #include "parser/cockatrice_xml_4.h"
 
@@ -92,6 +93,8 @@ LoadStatus CardDatabaseLoader::doLoadCardDatabases()
     emit loadingStarted();
     qCInfo(CardDatabaseLoadingLog) << "Card Database Loading Started";
 
+    ICardDatabaseParser::clearSetlist();
+
     CardDatabaseData data;
     LoadStatus loadStatus = NotLoaded;
 
@@ -126,6 +129,7 @@ LoadStatus CardDatabaseLoader::doLoadCardDatabases()
         qCInfo(CardDatabaseLoadingSuccessOrFailureLog) << "Card Database Loading Success";
         emit databaseDataReady(std::move(data));
         emit loadingFinished();
+        database->checkUnknownSets();
     } else {
         qCInfo(CardDatabaseLoadingSuccessOrFailureLog) << "Card Database Loading Failed";
         emit loadingFailed(); // bring up the settings dialog