hang interface on all RouterOS versions after 5-30 seconds

After installation RouterOS on the computer, always follows that: when I connect interface (ether1) to my home network, after about 3-10 seconds connection with the interface ether1 was lost. I tried two different cables, different versions of RouterOS 3.20, 3.30, 5.0RC3. After that, I tried two different computers, and I tried to connect to two different switches. I always got the same result. I assume that some specific traffic goes on my network. It also hang the interface. Problems with other network equipment isn’t present. If I directly connect the interface on computer with RouterOS to notebook all problems gone. If I start ping from WinBox any network device in my network the interface doesn’t fall off too. There are no messages in log.
How I can turned on debugging mode?
Sorry for my bad English.
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