解决办法：

打开 C:\Users\用户名\AppData\Local\Genymobile目录

打开genymotion.log文件，在里面最下面几行，找到如下日志

[Debug] Downloading file "http://files2.genymotion.com/dists/4.4.4/ova/genymotion_vbox86p_4.4.4_151118_000003.ova"
十二月 29 09:36:44 [Genymotion] [Debug] Start timer
十二月 29 09:36:57 [Genymotion] [Warning] QIODevice::write: device not open
十二月 29 09:36:57 [Genymotion] [Warning] QIODevice::write: device not open
十二月 29 09:37:19 [Genymotion] [Error] Connection Timeout

复制下载地址http://files2.genymotion.com/dists/4.4.4/ova/genymotion_vbox86p_4.4.4_151118_000003.ova 到下载器，下载好后，把文件复制到

C:\Users\用户名\AppData\Local\Genymobile\Genymotion\ova目录

重启Genymotion。