diff --git a/osrepodbmgr.Core/ChangeLog b/osrepodbmgr.Core/ChangeLog
index 98a2ce1..527543f 100644
--- a/osrepodbmgr.Core/ChangeLog
+++ b/osrepodbmgr.Core/ChangeLog
@@ -1,3 +1,9 @@
+2017-05-11  Natalia Portillo  <claunia@claunia.com>
+
+	* Workers.cs:
+	  Correct detection of which ZIP files must be copied and
+	  which ones must be recompressed.
+
 2017-05-11  Natalia Portillo  <claunia@claunia.com>
 
 	* Workers.cs:
diff --git a/osrepodbmgr.Core/Workers.cs b/osrepodbmgr.Core/Workers.cs
index 28a9a3b..2c448e1 100644
--- a/osrepodbmgr.Core/Workers.cs
+++ b/osrepodbmgr.Core/Workers.cs
@@ -1107,13 +1107,14 @@ namespace osrepodbmgr.Core
 
                 if(format == "Zip")
                 {
+                    Context.copyArchive = true;
                     ZipFile zf = ZipFile.Read(Context.path);
                     foreach(ZipEntry ze in zf)
                     {
                         // ZIP created with Mac OS X, need to be extracted with The UnArchiver to get correct ResourceFork structure
                         if(ze.FileName.StartsWith("__MACOSX", StringComparison.CurrentCulture))
                         {
-                            Context.copyArchive = true;
+                            Context.copyArchive = false;
                             break;
                         }
                     }