Ignore invalid shader cache index (Bug #1664)

extern/shiny/Main/Factory.cpp

@@ -51,6 +51,8 @@ namespace sh
 	{
 		assert(mCurrentLanguage != Language_None);
 
+		try
+		{
 			if (boost::filesystem::exists (mPlatform->getCacheFolder () + "/lastModified.txt"))
 			{
 				std::ifstream file;
@@ -69,6 +71,12 @@ namespace sh
 					mShadersLastModified[sourceFile] = modified;
 				}
 			}
+		}
+		catch (std::exception& e)
+		{
+			std::cerr << "Failed to load shader modification index: " << e.what() << std::endl;
+			mShadersLastModified.clear();
+		}
 
 		// load configurations
 		{