diff --git a/CHANGELOG.md b/CHANGELOG.md
index c6c05bd1..17bd8e86 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+# v1.2.10
+## XX/XX/2017
+
+1. [](#bugfix)
+    * Fixed issue with downloaded package when installing a testing release
+    
 # v1.2.9
 ## 01/18/2017
 
diff --git a/classes/gpm.php b/classes/gpm.php
index d16dd0e9..b43cd529 100644
--- a/classes/gpm.php
+++ b/classes/gpm.php
@@ -222,7 +222,11 @@ class Gpm
         $tmp_dir = Admin::getTempDir() . '/Grav-' . uniqid();
         Folder::mkdir($tmp_dir);
 
-        $filename = $package->slug . basename($package->zipball_url);
+        $bad_chars = array_merge(
+            array_map('chr', range(0, 31)),
+            array("<", ">", ":", '"', "/", "\\", "|", "?", "*"));
+
+        $filename = $package->slug . str_replace($bad_chars, "", basename($package->zipball_url));
 
         file_put_contents($tmp_dir . DS . $filename . '.zip', $contents);