diff --git a/Core/Net/NetFileCache.cs b/Core/Net/NetFileCache.cs
index 3c91a02211..6aec3f94cd 100644
--- a/Core/Net/NetFileCache.cs
+++ b/Core/Net/NetFileCache.cs
@@ -35,6 +35,13 @@ public class NetFileCache : IDisposable
         private static readonly Regex cacheFileRegex = new Regex("^[0-9A-F]{8}-", RegexOptions.Compiled);
         private static readonly ILog log = LogManager.GetLogger(typeof (NetFileCache));
 
+        static NetFileCache()
+        {
+            // SharpZibLib 1.1.0 changed this to default to false, but we depend on it for international mods.
+            // https://github.com/icsharpcode/SharpZipLib/issues/591
+            ZipStrings.UseUnicode = true;
+        }
+
         /// <summary>
         /// Initialize a cache given a GameInstanceManager
         /// </summary>
diff --git a/Tests/Core/Cache.cs b/Tests/Core/Cache.cs
index d93a8a06ea..aa1fb556c1 100644
--- a/Tests/Core/Cache.cs
+++ b/Tests/Core/Cache.cs
@@ -31,7 +31,7 @@ public void RemoveCache()
             cache.Dispose();
             cache = null;
             module_cache.Dispose();
-            module_cache = null;            
+            module_cache = null;
             Directory.Delete(cache_dir, true);
         }
 
@@ -206,6 +206,17 @@ public void ZipValid_ContainsFilenameWithBadChars_NoException()
             Thread.CurrentThread.CurrentUICulture = origUICulture;
         }
 
+        [Test]
+        public void ZipValid_ContainsFilenameWithUnicodeChars_Valid()
+        {
+            bool valid = false;
+            string reason = null;
+
+            Assert.DoesNotThrow(() =>
+                valid = NetFileCache.ZipValid(TestData.ZipWithUnicodeChars, out reason));
+            Assert.IsTrue(valid, reason);
+        }
+
         [Test]
         public void EnforceSizeLimit_UnderLimit_FileRetained()
         {
diff --git a/Tests/Data/TestData.cs b/Tests/Data/TestData.cs
index 88447d8339..d15615d219 100644
--- a/Tests/Data/TestData.cs
+++ b/Tests/Data/TestData.cs
@@ -124,6 +124,11 @@ public static string DogeCoinFlag_101_LZMA()
         /// </summary>
         public static readonly string ZipWithBadChars = DataDir("ZipWithBadChars.zip");
 
+        /// <summary>
+        /// Contains files with names that differ in their Unicode and "original" representation.
+        /// </summary>
+        public static readonly string ZipWithUnicodeChars = DataDir("ZipWithUnicodeChars.zip");
+
         ///<summary>
         /// DogeCoinFlag 1.01 info. This contains a bug where the
         /// install stanza doesn't actually refer to any files.
diff --git a/Tests/Data/ZipWithUnicodeChars.zip b/Tests/Data/ZipWithUnicodeChars.zip
new file mode 100644
index 0000000000..d5abf6ef88
Binary files /dev/null and b/Tests/Data/ZipWithUnicodeChars.zip differ
diff --git a/Tests/GUI/GH1866.cs b/Tests/GUI/GH1866.cs
index 8c5178f29f..91e077a615 100644
--- a/Tests/GUI/GH1866.cs
+++ b/Tests/GUI/GH1866.cs
@@ -15,6 +15,7 @@ namespace Tests.GUI
     /// which involves sorting the GUI table by Max KSP Version and then performing a repo operation.
     /// </summary>
     [TestFixture]
+    [NUnit.Framework.Category("Display")]
     public class GH1866
     {
         private CkanModule _anyVersionModule;