diff --git a/eeschema/symbol_lib_table.cpp b/eeschema/symbol_lib_table.cpp
index ef0d84f048..0a09426903 100644
--- a/eeschema/symbol_lib_table.cpp
+++ b/eeschema/symbol_lib_table.cpp
@@ -345,6 +345,8 @@ void SYMBOL_LIB_TABLE::LoadSymbolLib( std::vector<LIB_SYMBOL*>& aSymbolList,
     SYMBOL_LIB_TABLE_ROW* row = FindRow( aNickname, true );
     wxCHECK( row && row->plugin, /* void */  );
 
+    std::lock_guard<std::mutex> lock( row->GetMutex() );
+
     wxString options = row->GetOptions();
 
     if( aPowerSymbolsOnly )
@@ -375,7 +377,13 @@ LIB_SYMBOL* SYMBOL_LIB_TABLE::LoadSymbol( const wxString& aNickname, const wxStr
 {
     SYMBOL_LIB_TABLE_ROW* row = FindRow( aNickname, true );
 
-    if( !row || !row->plugin || !row->GetIsLoaded() )
+    if( !row || !row->plugin )
+        return nullptr;
+
+    // If another thread is loading this library at the moment; continue
+    std::unique_lock<std::mutex> lock( row->GetMutex(), std::try_to_lock );
+
+    if( !lock.owns_lock() )
         return nullptr;
 
     LIB_SYMBOL* symbol = row->plugin->LoadSymbol( row->GetFullURI( true ), aSymbolName,
diff --git a/include/lib_table_base.h b/include/lib_table_base.h
index 3cb96feca8..e8a9ef516c 100644
--- a/include/lib_table_base.h
+++ b/include/lib_table_base.h
@@ -180,6 +180,8 @@ public:
 
     void SetParent( LIB_TABLE* aParent ) { m_parent = aParent; }
 
+    std::mutex& GetMutex() { return m_loadMutex; }
+
     /**
      * Return the constant #PROPERTIES for this library (#LIB_TABLE_ROW).  These are
      * the "options" in a table.
@@ -244,6 +246,8 @@ private:
     LIB_TABLE*        m_parent;           ///< Pointer to the table this row lives in (maybe null)
 
     std::unique_ptr< PROPERTIES > properties;
+
+    std::mutex        m_loadMutex;
 };