Exclamation MTP Connection on Windows 8.1 64bit

I tried to connect my G2 with Dell Windows 8.1 64bit laptop. The connection is made (MTP) but it doesn't last (just some minutes). I tried again with my Nexus 10 and the problem is same.

Could anybody give any solution? Thanks.

NOKIA LUMIA 928 - Windows Phone 8 - Lumia Amber (GDR2)
GOOGLE NEXUS 10 - Official SlimKat
SONY XPERIA Z1 - Rooted 4.3 Stock