diff --git a/RoR2VersionSelector/RoR2VersionSelector.cs b/RoR2VersionSelector/RoR2VersionSelector.cs
index ac4104028..178025f86 100644
--- a/RoR2VersionSelector/RoR2VersionSelector.cs
+++ b/RoR2VersionSelector/RoR2VersionSelector.cs
@@ -91,10 +91,32 @@ private void RoR2VersionSelector_Load(object sender, EventArgs e)
             UpdateInitialState();
         }
 
+        private Boolean ValidateInput()
+        {
+            if (TextBoxUsername.Text.Length == 0)
+            {
+                MessageBox.Show("Please specify username.", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Information);
+                return false;
+            }
+
+            if (!Enum.IsDefined(typeof(RoR2Versions), ComboBoxVersionSelector.Text))
+            {
+                MessageBox.Show("Please specify valid version.", "Invalid", MessageBoxButtons.OK, MessageBoxIcon.Information);
+                return false;
+            }
+
+            return true;
+        }
+
         private async void ButtonDownloadDepot_Click(object sender, EventArgs e)
         {
+            if (!ValidateInput())
+            {
+                return;
+            }
             ButtonDownloadDepot.Enabled = false;
 
+
             var startInfo = new ProcessStartInfo
             {
                 FileName = "cmd.exe",