diff --git a/CTCDefaults.h b/CTCDefaults.h
index 9d7c146..35c5824 100644
--- a/CTCDefaults.h
+++ b/CTCDefaults.h
@@ -21,6 +21,8 @@ extern NSString * const kCTCDefaultsServiceFeedURLPrefix;
 + (void)refreshLoginItemStatus;
 
 + (BOOL)isConfigurationValid;
++ (BOOL)isFeedURLValid;
++ (BOOL)isTorrentsSavePathValid;
 
 + (NSString *)appName;
 
diff --git a/CTCDefaults.m b/CTCDefaults.m
index 6c89888..68f6d21 100644
--- a/CTCDefaults.m
+++ b/CTCDefaults.m
@@ -91,23 +91,8 @@ + (void)refreshLoginItemStatus {
     [CTCLoginItems toggleRegisteredAsLoginItem:[NSUserDefaults.standardUserDefaults boolForKey:kCTCDefaultsOpenAtLoginKey]];
 }
 
-+ (BOOL)isConfigurationValid {
-	// Validate torrent folder. This should never fail!
-	NSString *torrentFolder = self.torrentsSavePath;
-	
-	if (!torrentFolder) return NO;
-    
-	BOOL isDirectory = NO;
-	if ([NSFileManager.defaultManager fileExistsAtPath:torrentFolder
-                                           isDirectory:&isDirectory]) {
-		if (!isDirectory) return NO;
-	}
-    else {
-		return NO;
-	}
-    
-	// Most importantly, validate feed URL
-	NSString *feedURL = CTCDefaults.feedURL;
++ (BOOL)isFeedURLValid {
+    NSString *feedURL = CTCDefaults.feedURL;
 	if (![feedURL hasPrefix:kCTCDefaultsServiceFeedURLPrefix]) {
 		// The URL should start with the prefix!
 		NSLog(@"Feed URL (%@) does not start with expected prefix (%@)", feedURL, kCTCDefaultsServiceFeedURLPrefix);
@@ -122,6 +107,27 @@ + (BOOL)isConfigurationValid {
 	return YES;
 }
 
++ (BOOL)isTorrentsSavePathValid {
+    NSString *torrentFolder = self.torrentsSavePath;
+	
+	if (!torrentFolder) return NO;
+    
+	BOOL isDirectory = NO;
+	if ([NSFileManager.defaultManager fileExistsAtPath:torrentFolder
+                                           isDirectory:&isDirectory]) {
+		if (!isDirectory) return NO;
+	}
+    else {
+		return NO;
+	}
+    
+    return YES;
+}
+
++ (BOOL)isConfigurationValid {
+    return self.isTorrentsSavePathValid && self.isFeedURLValid;
+}
+
 + (NSString *)infoStringForKey:(NSString *)key {
     return [NSBundle.mainBundle objectForInfoDictionaryKey:key];
 }
diff --git a/CTCPreferencesController.m b/CTCPreferencesController.m
index f2d848c..16b6a44 100644
--- a/CTCPreferencesController.m
+++ b/CTCPreferencesController.m
@@ -1,6 +1,7 @@
 #import "CTCPreferencesController.h"
 #import "CTCDefaults.h"
 #import "CTCScheduler.h"
+#import "NSWindow+ShakeAnimation.h"
 
 
 @implementation CTCPreferencesController
@@ -12,7 +13,7 @@ - (void)awakeFromNib {
     if (!CTCDefaults.isConfigurationValid) [self showWindow:self];
 }
 
-- (void)showWindow:(id)sender {
+- (IBAction)showWindow:(id)sender {
     [NSApp activateIgnoringOtherApps:YES];
     [super showWindow:sender];
 }
@@ -20,17 +21,22 @@ - (void)showWindow:(id)sender {
 - (IBAction)savePreferences:(id)sender {
 	[CTCDefaults save];
 	
-    // If the feed URL is invalid, just warn user
-    if (!CTCDefaults.isConfigurationValid) {
-		[self showBadURLAlert];
-        return;
+    if (CTCDefaults.isConfigurationValid) {
+        // Hide the Preferences window
+        [self.window close];
+        
+        // Also force check
+        [CTCScheduler.sharedScheduler forceCheck];
+    }
+    else {
+        // Show the Feeds tab because all possible invalid inputs are currently there
+        [self showFeeds:self];
+        
+        // Shake the window to signal invalid input
+        [self.window performShakeAnimation];
+        
+		//[self showBadURLAlert];
     }
-    
-    // Hide the Preferences window
-    [self.window close];
-    
-    // Also force check
-    [CTCScheduler.sharedScheduler forceCheck];
 }
 
 - (IBAction)showFeeds:(id)sender {
@@ -44,8 +50,6 @@ - (IBAction)showTweaks:(id)sender {
 }
 
 - (void)showBadURLAlert {
-	[self showFeeds:self];
-    
     // Show an alert warning the user: the feed URL is invalid
     NSAlert *badURLAlert = NSAlert.new;
     badURLAlert.messageText = NSLocalizedString(@"badurl", @"Message for bad feed URL in preferences");
diff --git a/Catch.xcodeproj/project.pbxproj b/Catch.xcodeproj/project.pbxproj
index fed8116..c3fd473 100644
--- a/Catch.xcodeproj/project.pbxproj
+++ b/Catch.xcodeproj/project.pbxproj
@@ -35,6 +35,8 @@
 		44717ADD1913AF3400580054 /* CTCFileUtils.m in Sources */ = {isa = PBXBuildFile; fileRef = 44717AA91913173600580054 /* CTCFileUtils.m */; };
 		448CC7E817FE1F840063D3FD /* Sparkle.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 448CC7E617FE1F840063D3FD /* Sparkle.framework */; };
 		44EAD12E1916682D002C7443 /* CTCApplication.m in Sources */ = {isa = PBXBuildFile; fileRef = 44EAD12D1916682D002C7443 /* CTCApplication.m */; };
+		44FBC67B196312A400434B01 /* QuartzCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 44FBC67A196312A400434B01 /* QuartzCore.framework */; };
+		44FBC67E196316E900434B01 /* NSWindow+ShakeAnimation.m in Sources */ = {isa = PBXBuildFile; fileRef = 44FBC67D196316E900434B01 /* NSWindow+ShakeAnimation.m */; };
 		8D11072D0486CEB800E47090 /* main.m in Sources */ = {isa = PBXBuildFile; fileRef = 29B97316FDCFA39411CA2CEA /* main.m */; settings = {ATTRIBUTES = (); }; };
 		8D11072F0486CEB800E47090 /* Cocoa.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 1058C7A1FEA54F0111CA2CBB /* Cocoa.framework */; };
 /* End PBXBuildFile section */
@@ -147,6 +149,9 @@
 		448CECE219157BDF0075ADD9 /* zh-Hant */ = {isa = PBXFileReference; fileEncoding = 10; lastKnownFileType = text.plist.strings; name = "zh-Hant"; path = "zh-Hant.lproj/UI.strings"; sourceTree = "<group>"; };
 		44EAD12C1916682D002C7443 /* CTCApplication.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CTCApplication.h; sourceTree = "<group>"; };
 		44EAD12D1916682D002C7443 /* CTCApplication.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = CTCApplication.m; sourceTree = "<group>"; };
+		44FBC67A196312A400434B01 /* QuartzCore.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = QuartzCore.framework; path = System/Library/Frameworks/QuartzCore.framework; sourceTree = SDKROOT; };
+		44FBC67C196316E900434B01 /* NSWindow+ShakeAnimation.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "NSWindow+ShakeAnimation.h"; sourceTree = "<group>"; };
+		44FBC67D196316E900434B01 /* NSWindow+ShakeAnimation.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSWindow+ShakeAnimation.m"; sourceTree = "<group>"; };
 		8D1107310486CEB800E47090 /* Catch-Info.plist */ = {isa = PBXFileReference; explicitFileType = text.plist.xml; fileEncoding = 4; path = "Catch-Info.plist"; sourceTree = "<group>"; };
 		8D1107320486CEB800E47090 /* Catch.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Catch.app; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
@@ -172,6 +177,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				44FBC67B196312A400434B01 /* QuartzCore.framework in Frameworks */,
 				8D11072F0486CEB800E47090 /* Cocoa.framework in Frameworks */,
 				38F9B09111C98E9E0021C540 /* Automator.framework in Frameworks */,
 				448CC7E817FE1F840063D3FD /* Sparkle.framework in Frameworks */,
@@ -242,6 +248,7 @@
 		29B97323FDCFA39411CA2CEA /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				44FBC67A196312A400434B01 /* QuartzCore.framework */,
 				29B97325FDCFA39411CA2CEA /* Foundation.framework */,
 				29B97324FDCFA39411CA2CEA /* AppKit.framework */,
 				38F9B09011C98E9E0021C540 /* Automator.framework */,
@@ -257,6 +264,8 @@
 			children = (
 				4456EE5F1916D20000B3FF1A /* NSDate+TimeOfDayMath.h */,
 				4456EE601916D20000B3FF1A /* NSDate+TimeOfDayMath.m */,
+				44FBC67C196316E900434B01 /* NSWindow+ShakeAnimation.h */,
+				44FBC67D196316E900434B01 /* NSWindow+ShakeAnimation.m */,
 			);
 			name = Categories;
 			sourceTree = "<group>";
@@ -529,6 +538,7 @@
 				38D39B6011C3A6E100C17C80 /* CTCMenuController.m in Sources */,
 				3803C7AE11C3DA9300FC08DB /* CTCAppDelegate.m in Sources */,
 				446298EB191655080045EC72 /* CTCPreferencesController.m in Sources */,
+				44FBC67E196316E900434B01 /* NSWindow+ShakeAnimation.m in Sources */,
 				44717AA71913072200580054 /* CTCLoginItems.m in Sources */,
 				3803C7EC11C3E7AD00FC08DB /* CTCScheduler.m in Sources */,
 				44717AAA1913173600580054 /* CTCFileUtils.m in Sources */,
diff --git a/NSWindow+ShakeAnimation.h b/NSWindow+ShakeAnimation.h
new file mode 100644
index 0000000..66d2788
--- /dev/null
+++ b/NSWindow+ShakeAnimation.h
@@ -0,0 +1,8 @@
+#import <Cocoa/Cocoa.h>
+
+
+@interface NSWindow (ShakeAnimation)
+
+- (void)performShakeAnimation;
+
+@end
diff --git a/NSWindow+ShakeAnimation.m b/NSWindow+ShakeAnimation.m
new file mode 100644
index 0000000..bc04287
--- /dev/null
+++ b/NSWindow+ShakeAnimation.m
@@ -0,0 +1,30 @@
+#import <QuartzCore/QuartzCore.h>
+#import "NSWindow+ShakeAnimation.h"
+
+
+@implementation NSWindow (ShakeAnimation)
+
+- (void)performShakeAnimation {
+    // Stolen from: http://stackoverflow.com/questions/10517386
+    static int numberOfShakes = 2;
+    static float durationOfShake = 0.3f;
+    static float vigourOfShake = 0.015f;
+    
+    CGRect frame = self.frame;
+    CAKeyframeAnimation *shakeAnimation = CAKeyframeAnimation.animation;
+    
+    CGMutablePathRef shakePath = CGPathCreateMutable();
+    CGPathMoveToPoint(shakePath, NULL, NSMinX(frame), NSMinY(frame));
+    for (NSInteger index = 0; index < numberOfShakes; index++){
+        CGPathAddLineToPoint(shakePath, NULL, NSMinX(frame) - frame.size.width * vigourOfShake, NSMinY(frame));
+        CGPathAddLineToPoint(shakePath, NULL, NSMinX(frame) + frame.size.width * vigourOfShake, NSMinY(frame));
+    }
+    CGPathCloseSubpath(shakePath);
+    shakeAnimation.path = shakePath;
+    shakeAnimation.duration = durationOfShake;
+    
+    self.animations = @{@"frameOrigin": shakeAnimation};
+    [self.animator setFrameOrigin:self.frame.origin];
+}
+
+@end